EMQX Enterprise Version 4

4.4.25

Release Date: 2024-09-13

Enhancements

• Introduced a username quota limitation module to restrict the number of sessions that a single MQTT username can log in with.

  This feature can be configured in the Dashboard under Modules -> Username Quota. In the Configuration tab, you can add a username white list, where usernames in the white list will not be subject to quota restrictions.

  Note that if this feature is enabled, a whitelist must be used to bypass the username quota restrictions for MQTT bridging.

• Improved error log when an illegal Will QoS value is carried in the CONNECT message when using the MQTT 3.1.1 protocol.

• Enhanced performance for sending messages to Redis.

  Previously, due to the limitations of the gen_tcp:send/2 implementation, as more messages piled up in the Redis Client process’s send queue, the sending performance would gradually decrease. Thus, under high message traffic, the Redis Client process could become a system bottleneck.

  This optimization improves the sending performance of Redis Authentication/ACL, Redis Plugin, and Redis Rule Engine resources. For Redis authentication functionality, it relieves the pressure during mass device reconnections after a service interruption.

• Enhanced performance for sending messages to SysKeeper.

  Previously, due to the limitations of the gen_tcp:send/2 implementation, as more messages piled up in the emqx_bridge_sysk_forward process’s send queue, the sending performance would gradually decrease. Thus, under high message traffic, the emqx_bridge_sysk_forward process could become a system bottleneck.

• Increased the file size limit for a single log trace from 512MB to 1GB.

• Improved the ACL feature in the "Internal DB AUTH/ACL" module.

  • You can now set a limit on the number of ACL entries for a single client in the built-in ACL module.

    When publishing or subscribing to a topic, ACL validation requires traversing the client’s ACL entries. Therefore, adding too many ACL entries for a single client could degrade the performance of publishing or subscribing. You can now limit the number of ACL entries added for a single client using the auth.mnesia.max_acls_for_each_login configuration item or the Max ACLs"parameter in the module.

  • Enhanced the matching performance of the built-in ACL module.

    By optimizing the storage structure of the ACL table and the topic matching logic, the performance of searching and matching ACL entries in the built-in ACL module has been improved. The more ACL entries a single client has, the more significant the performance improvement.

  • Added/removed ACL entries in the built-in ACL module will now reset the ACL cache.

• The rule engine's batch sending process now supports overload protection.

  When batch sending is enabled, the rule engine creates a group of processes to buffer and batch send messages for actions. If asynchronous sending mode is used, when the external database response is too slow, messages may pile up in the batch process’s message queue, posing a risk of exceeding system memory limits. Now, the batch sending function of the rule engine will be limited by overload protection. When the message queue size exceeds "Maximum Batch Size" * 10 (if the value of "Maximum Batch Size" * 10 is less than 1000, then the minimum message queue size is 1000), the action will be "unloaded" for a period of time (default 60 seconds). During this time, subsequent messages sent to the action will be discarded, and the action_olp_blocked/<RuleID>/<ActionID> alarm will be triggered.

  Actions subject to overload protection:

  • Data to Cassandra
  • Data to ClickHouse
  • Data to DolphinDB
  • Data to InfluxDB
  • Data to IoTDB
  • Data to Lindorm
  • Data to MySQL
  • Data to Oracle Database
  • Data to PostgreSQL
  • Data to SQLServer
  • Data to Tablestore
  • Data to TDengine
  • Data to GCP Pubsub

• Added support for inserting undefined values as NULL into databases.

  Various database actions in the rule engine support constructing insert statements using ${var} placeholders. Previously, if a placeholder variable was undefined, the rule engine might insert the string undefined into the database. Now, a new option Insert Undefined Values as NULL has been added to the database-related actions, allowing NULL to be inserted into the database when a variable is undefined.

  Actions supporting this option:

  • Data to Cassandra
  • Data to ClickHouse
  • Data to DolphinDB
  • Data to MySQL
  • Data to Oracle Database
  • Data to PostgreSQL
  • Data to SQLServer
  • Data to TDengine

• Added support for log throttling.

  When certain abnormal situations occur, a large number of repetitive (similar content) logs may be generated, increasing system load and potentially overshadowing other useful log information. Now, you can configure a time window and maximum log rate within that window using the log.throttling setting in the etc/logger.conf file.

  Note that to improve the efficiency of the throttling function, EMQX will start N throttlers, where N is the number of CPU cores. This means that if log.throttling = 50,60s is set, each throttler will restrict the logging of the same message (determined by the log’s module name and line number) to a maximum of 50 times per minute. Assuming 8 CPU cores, the system could log between 50 and 400 messages per minute depending on Erlang VM process scheduling. If logs are dropped by the throttler, EMQX will log a message indicating the number of logs that were dropped:

  log throttled during last 60s, dropped_msg: #{{emqx_channel,1400} => #{msg => "Client ~s (Username: '~s') login failed for ~0p", count => 33}}

  This log indicates that in the last 60 seconds, 33 logs from line 1400 of the emqx_channel module were dropped by EMQX.

  This feature is enabled by default for warning and higher log levels, with a default setting of 50,60s.

• Added support for configuring HTTP/HTTPS management interface timeouts.

  Two timeout-related configurations have been added to the etc/plugins/emqx_management.conf file:

  • management.listener.<Proto>.request_timeout: Specifies the time after establishing a TCP connection within which the server will close the connection if no HTTP request is received. The default is 5 seconds.
  • management.listener.<Proto>.idle_timeout: Specifies the idle timeout period. After receiving at least one HTTP request on the connection, if no further requests are received, the server will close the connection after the specified time. The default is 60 seconds.

  Here, <Proto> can be http or https.

• Added validation for the target topic in the "Republish" action.

  After the improvement, when the "Republish" action sends a message, it will validate the legality of the target topic. If the topic is a non-UTF-8 encoded binary, the action will fail.

• Optimized the performance of the Redis-Cluster driver.

  This optimization reduces the memory footprint of EMQX when accessing Redis Cluster. The following features benefit from this optimization:

  • Redis Authentication/ACL
  • Redis Plugin
  • Redis Actions in the Rule Engine

Bug Fixes

• Fixed an issue where sending messages exceeding Kafka server's maximum message size limit would cause the Kafka Producer to become blocked.

  Previously, when a single message exceeded the message.max.bytes configured on the Kafka server, the Kafka Producer's send queue in the rule engine would become blocked, and subsequent messages would be buffered until reaching the maximum cache limit set by Max Cache Bytes. Now, if a single message exceeds the Max Batch Bytes limit configured in the rule engine's Kafka resource, the Kafka Producer will discard the message to prevent queue blockage.

• Fixed an issue where the "resource down" alarm could not be cleared in certain situations.

• Fixed an issue where the timestamp field value was incorrect in rules triggered by Will messages. The field value should represent the time the rule was triggered, not the client's connection time.

• Fixed an issue where the Kafka action failed to send data when username was used as the Message Key.

  Previously, if the Kafka Message Key was set to username but the MQTT client did not provide a username at login, the Kafka Producer would fail to send the message. After the fix, for messages without a username, the Kafka Producer will use the string undefined as the Message Key.

• Fixed an issue where the rule engine failed to trigger the $events/client_disconnected event when a process terminated unexpectedly.

• Fixed an issue where the DynamoDB action failed to send data when clientid was set as the Hash Key.

• Fixed an issue which may cause shared-subscription sticky strategy degrading into random after node restart.

4.4.24

Release Date: 2024-04-16

Enhancements

• Make /load_rebalance/availability_check public, i.e. not requiring authentication. This simplifies load balancer setup. Also make this API method maximally lightweight to avoid possible overloading the broker.

• Made rebalance/evacuation more graceful during the wait health check phase. The connections to nodes marked for eviction are now not prohibited during this phase.

  During this phase it is unknown whether these nodes are all marked unhealthy by the load balancer, so prohibiting connections to them may cause multiple unsuccessful attempts to reconnect.

• Improved the issue of a too short Idle Timeout for the HTTP API.

  Previously, the idle_timeout for the HTTP API was set to 5 seconds. If the HTTP API did not receive any requests within 5 seconds, the TCP connection of HTTP would be closed by EMQX. This change increases the HTTP API's idle_timeout to 60 seconds.

• Enhanced the descriptions of certain configuration fields and options.

  • Improved descriptions of the Base URL and Path parameters in Webhook resources and actions.
  • Enhanced the description of the idle_timeout configuration for WS/WSS listeners in hot configurations.
  • Improved the detailed description of the Max Returned Count parameter in offline message-related actions.
  • Renamed the English parameter Key in ClickHouse resources to Password.
  • Renamed the PartitionKey parameter in HStreamDB actions to Partition Key.
  • Updated the detailed description of the Maximum Retained Message Size parameter in the Retainer module from 0B to 0.
  • Renamed Message Interception to Intercept Empty Messages in the Retainer module and improved its description.

• Checked the value ranges and validity of certain configuration options.

  • Checked that the mqtt.max_topic_levels, mqtt.max_packet_size, keepalive_backoff configuration options must be non-negative.
  • When starting SSL listeners, checked the dependencies of the verify_peer, fail_if_no_peer_cert, and cacertfile parameters. Previously, this check only occurred when SSL clients attempted to establish a connection.
  • Checked that the acceptors, max_connections, max_conn_rate, and active_n parameters in listener configurations must be non-negative.
  • Checked that the Heartbeat Interval and Automatic Reconnection Interval parameters in RabbitMQ resources must be correct time length strings.
  • Fixed an issue where duplicate ports were not checked for GB/T 32960 and JT/T808 listeners.
  • Fixed an issue in the GB/T 32960 and JT/T808 gateway configurations where certain parameter values were not validated.

• Optimized log formats and addressed some display issues on the Dashboard.

  • Improved the precision of rule engine rate values occasionally showing very long floating-point numbers on the Dashboard, now accurate to two decimal places.
  • In the alert messages for system resource usage, the CPU usage value is now precise to two decimal places.
  • Removed debug fields like mfa from logs.

• Rule engine now supports user-defined SQL functions.

  Assuming a user-customized plugin contains a module named emqx_rule_funcs1 with a function named func, in the rule engine, users can use it like this:

  SELECT emqx_rule_funcs1.func() FROM "t/#"

  Note that the module name must be prefixed with either emqx_rule_funcs or EmqxRuleFuncs.

• The Kafka consumer group module now supports more authentication methods.

  Now, the Kafka consumer group module supports multiple authentication methods, including PLAIN, SCRAM_SHA_256, and KERBEROS, just like Kafka resources.

• Added overload protection for certain HTTP API methods that consume more system resources.

  • The GET /api/v4/clients/* related APIs
  • The GET /api/v4/routes API
  • The GET /api/v4/subscriptions API
  • The GET /api/v4/rules API
  • The GET /api/v4/banned API
  • The GET /api/v4/audits API
  • APIs for searching usernames and client IDs in the built-in authentication module.

Bug Fixes

• Fixed the date_to_unix_ts() SQL function in the rule engine returns an incorrect value when the input date is a leap year.

• During node evacuation, evacuate all disconnected sessions, not only those started with clean_start set to false.

  Before the fix, if the client sets clean_start = true and a non-zero Session-Expiry-Interval, the session will not be evacuated, resulting in the loss of the session after the node is closed.

• Fixed the Redis authentication exception when corresponding authentication information is not found in Redis.

• Fixed the exception caused by uninitialized ETS table during the startup process of an EMQX node when accessing the HTTP API.

• Fixed the issue of failing to load extension plugins under certain circumstances.

  The plugins.expand_plugins_dir configuration can specify a directory where EMQX will search for and load plugins during startup. Under certain circumstances, plugin files may be loaded multiple times, causing EMQX to fail to start.

• Fixed the issue of being unable to clear the ACL cache for a single client using the command line.

  Previously, the command emqx ctl acl cache-clean 'mqttx_458d5222' did not work.

• Fixed the problem where fuzzy searches on the rule list, built-in authentication/authorization list pages did not show more pagination, causing incomplete data display.

• Fixed the inaccurate error logs printed by EMQX when attempting to download trace log files in the "waiting to start" state.

• Fixed the issue with the SSL listener configuration during the first use of the hot configuration feature, where the backlog configuration item was displayed as empty and required, causing form submission failure.

  After the fix, the backlog configuration is made optional with a default value of 1024.

• Fixed the issue where validators related to zone in the configured emqx.schema file were not effective.

• Fixed the problem in the response of the audit log query API, where the operation_result field remained success even when the HTTP Status Code for the queried information was 500.

• Fixed the issue of duplicate GB/T 32960 client IDs on the Dashboard.

4.4.23

Release Date: 2023-11-24

Enhancements

• Improved the performance of message sending between EMQX nodes.

  gen_rpc is the RPC channel used internally by EMQX for sending MQTT messages between nodes. In this improvement, we optimized the gen_rpc's ability to handle backlogged messages in the channel, allowing the system to recover more quickly from traffic peaks.

Bug Fixes

• Fixed the issue that the rule engine could not connect to upstash Redis.

  Before the fix, after establishing a TCP connection with the Redis service, the Redis driver of emqx used Inline Commands to send AUTH and SELECT commands. However, the upstash Redis service did not support Inline Commands, which caused the rule engine to fail to connect to the upstash Redis service. After the fix, the redis driver of emqx uses RESP (REdis Serialization Protocol) to send AUTH and SELECT commands.

• Added validity check for some parameters of the "Offline Msg to Redis" action and Redis resource.

  • Checked the "Redis Key TTL" parameter of the "Offline Msg to Redis" action.
  • Checked the "Redis Database" parameter of the Redis resource.

4.4.22

Release Date: 2023-11-01

Enhancements

• Added the Audit Log feature to track important operation changes.

  • To enable the Audit Log, click General -> Audit Log -> Enable on Dashboard, modify the parameters, and click Add.
  • Once enabled, all HTTP requests except GET and CLI executions will be recorded.
  • The most recent 5,000 audit log entries are visible by default in the Dashboard, while the complete log file is stored in the data/audit directory.

• Added support for Role-Based Access Control (RBAC) roles in the dashboard. With this new functionality, users can be assigned one of two roles: "Administrator" or "Viewer" when logging into the Dashboard, each with distinct permissions.

  • Administrator Role: Administrators enjoy unrestricted access, granting them full control over all aspects of the dashboard's functionality.
  • Viewer Role: Viewers are limited to read-only access. They can view dashboard information but are unable to make any modifications.

  RBAC ensures that the right users have the appropriate level of access, simplifying user management and access control and enhancing security and data integrity.

• LwM2M gateway supported sending downlink data using Block Wise Transfer.

• Added the new SQL functions: map_keys(), map_values(), map_to_entries(), join_to_string(), join_to_string(), join_to_sql_values_string(), is_null_var(), is_not_null_var().

  For more information on the functions and their usage, refer to the documentation.

• Added Forward QoS configuration option for the action of "Data bridge to MQTT Broker" to specify the QoS level of messages to be forwarded through the MQTT bridge.

• Added support for specifying the expiration time of MQTT messages via configuration file.

  See the description of the mqtt.message_expiry_interval configuration in the emqx.conf file for more details.

• Updated Erlang/OTP version to OTP-24.3.4.2-4.

• Added schema validations for better configuring OCSP Stapling and CRL Check consistency.

Bug Fixes

• Resolved the issue causing the Kafka client (wolff) producer to crash.

  This problem occurred when a Kafka resource was inadvertently deleted during the initialization of certain rules, leading to a failure in the dependent rules. This error then propagated, triggering an error escalation mechanism, leading to the crash of all rules. The resolution prevents this propagation, ensuring the system stability.

• Fixed the issue that GBT32960 gateway module could not parse the retry_interval parameter.

• Fixed the issue that GBT32960 client was unable to fetch through the HTTP API.

• Fixed the issue that exception logs appeared when the OCPP client failed in authentication.

• Fixed the issue that OCPP gateway did not validate an empty ClientID.

• Upgraded RabbitMQ driver and fixed some security vulnerabilities.

• Fixed the issue with the GCP PubSub action in the rule engine, where the statistics counter did not increase in asynchronous sending mode.

• Fixed the issue that only the resources of the current node would reconnect when manually reconnecting resources.

• Fixed the issue that the statistics counter of actions was not reset after deleting and reimporting rules.

• Fixed the issue in cluster mode where restarting rules would result in an action resource leak.

  Before the fix, when stopping and starting rules, the action resource (some processes associated with the actions) leaked if the action creation failed on certain nodes.

• Fixed the issue of reduced performance in some data integration actions with batch mode in multi-CPU scenarios compared to versions before 4.4.5.

  In version 4.4.5, the number of workers in the batch process pool was modified to number of CPU cores * 4. When running on machines with a higher number of CPU cores, this resulted in an excessive number of worker processes, causing each process to accumulate relatively few messages within the specified batch time. This, in turn, led to a decrease in the performance of batch data sending.

  The fix no longer hardcodes the number of workers in the batch process pool. Instead, it introduces a new configuration option called batch_pool_size, with a default value of 8.

  The data integration actions affected are: data_to_cassa, data_to_clickhouse, data_to_influxdb, data_to_iotdb, data_to_lindorm, data_to_mysql, data_to_oracle, data_to_pgsql, data_to_sqlserver, data_to_tablestore, data_to_tdengine, data_to_gcp_pubsub.

• Fixed an issue in the MQTT bridge that sending QoS2 messages failed when using the MQTT 5.0 protocol.

• Fixed the issue that hot configuration updates failed when the configuration for a listener in the configuration file was missing.

• Fixed the issue of LwM2M gateway plugin startup failure.

  Before the fix, if the LwM2M module was first shut down and then the LwM2M plugin was started, it would result in a plugin startup failure. The log message was as follows:

  {emqx_lwm2m,{bad_return,{{emqx_lwm2m_app,start,[normal,[]]},{'EXIT',{{already_started,<0.3895.177>},[...]}}}}}

• Fixed the issue that the shared subscription topic prefix on the Dashboard was not displayed correctly.

  Before the fix, topics like $share/g//t would be displayed as /t on the client details page of the Dashboard, causing the shared subscription prefix to be lost. After the fix, it will be displayed correctly as $share/g//t.

• Added a none option for peer_cert_as_username and peer_cert_as_clientid in the configuration file. These two options are used to use (client) certificate content as the username/ClientID.

• Fixed the issue of occasional listener restarts when enabling hot configuration feature.

• Fixed the issue that errors occurred when stopping actively running rules.

  Before the fix, manually stopping actively running rules occasionally resulted in error logs like the following, indicating that the action was not properly initialized or had been cleared:

  foo@x.x.x.x:54663 Rule: <<"rule:ba48182b">>; Action: data_to_kafka; Resource: <<"resource:7bacacdc">>. Continue next action, reason: {error,{badmatch,not_found}, ...

  After the fix, such error logs are no longer generated, and error logs for uninitiated actions in other cases have been optimized.

• Fixed the issue of DTLS PSK handshake failure in the LwM2M gateway.

• Added checks for illegal fields in the retainer module's configuration.

  Added checks for the Max Retained Messages and Max Retained Payload Size fields to ensure they are non-negative values.

• Fixed the issue of failing to send messages to TDEngine after hot update.

• Fixed the issue of RabbitMQ resources becoming unavailable after hot update.

• Canceled the HTTP refresh timer of the OCSP when disabling OCSP stapling or the TLS listener.

• Canceled the CRL refresh timer when disabling CRL check or the TLS listener.

4.4.21

Release Date: 2023-10-16

Enhancements

• Added support for Confluent data bridge.

• Now the MQTT topic field in the Kafka consumer group supports templates with placeholders.

  For example, if the key of the message consumed by Kafka is "a", and the configured MQTT topic is "topic/${key}", then the MQTT topic will be replaced with "topic/a" when the message is forwarded.

• Now the "Message Republish" action supports two new fields: "MQTT Properties" and "User Properties". Both of the fields are in the format of key-value pairs, and both the key and value support placeholders.

Bug Fixes

• Fixed the issue that the Kafka action cannot send numeric values as Kafka Headers.

  Prior to this fix, when the "Kafka Headers value encode mode" was set to "NONE", if the "Kafka Headers" field contains a JSON object with numeric types (such as {"a": 1, "b": "str"}), the numeric values ("a":1) would be ignored and not sent to Kafka. After the fix, the numeric types in JSON will be converted to strings before being sent to Kafka.

4.4.20

Release Date: 2023-08-01

Enhancements

• Improved the performance of sending data to Kafka and HStreamDB.

  This enhancement added an Erlang message buffer ahead of the driver process, reducing the frequency of internal message passing within EMQX. This optimization comes at the expense of increased message latency, but it significantly enhances the throughput capacity when sending data to Kafka and HStreamDB.

  Now, messages sent from EMQX to Kafka or HStreamDB drivers will first enter the buffer. When the number of cached messages reaches message_accumulation_size or the time interval reaches message_accumulation_interval, the buffered messages will be batched and sent to the Kafka or HStreamDB driver. The driver will then handle the forwarding to Kafka or HStreamDB services. Setting message_accumulation_size = 0 (default value) will disable this message buffering feature.

• Added the auto_reconnect option for SQL Server resources.

  Before this improvement, when the connection between EMQX and the SQL Server database was disrupted, EMQX was unable to reconnect automatically. With this new enhancement, EMQX can reconnect automatically. You can still opt to set auto_reconnect = false to turn off the automatic reconnection feature.

• Added TLS connection support to RabbitMQ resource.

• Added support for defining attributes and ordering key for GCP PubSub actions.

Bug Fixes

• Fixed the issue that the mongo_date() function of the rule engine cannot be tested on the Dashboard.

  Before the fix, mongo_date() can be used normally, but an error will occur when testing on the SQL test page of the Dashboard.

• Fixed the issue where the rule engine failed to send messages through RabbitMQ actions after a hot upgrade to version 4.4.19.

4.4.19

Release Date: 2023-06-27

Enhancements

• Added support for TCP keep-alive in MQTT/TCP and MQTT/SSL listeners #10854.

  A new configuration option has been added: zone.<zone-name>.tcp_keepalive = Idle,Interval,Probes. Users can enable the TCP layer's Keep Alive feature and specify time parameters using this configuration. This configuration is only effective on Linux and MacOS systems.

• Improved error logs related to Proxy Protocol emqx/esockd#177.

  The sample logs before this improvement:

  2023-04-20T14:56:51.671735+08:00 [error] supervisor: 'esockd_connection_sup - <0.2537.0>', errorContext: connection_shutdown, reason: {invalid_proxy_info,<<"f\n">>}, offender: [{pid,<0.3192.0>},{name,connection},{mfargs,{...}}]
  
  2023-04-20T14:57:01.348275+08:00 [error] supervisor: 'esockd_connection_sup - <0.2537.0>', errorContext: connection_shutdown, reason: {proxy_proto_timeout,5000}, offender: [{pid,<0.3194.0>},{name,connection},{mfargs,{...}}]

  After the improvement:

  2023-04-20T18:07:06.180134+08:00 [error] [esockd_proxy_protocol] The listener 127.0.0.1:8883 is working in proxy protocol mode, but received invalid proxy_protocol header, raw_bytes=<<"f\n">>
  
  2023-04-20T18:10:17.205436+08:00 [error] [esockd_proxy_protocol] The listener 127.0.0.1:8883 is working in proxy protocol mode, but timed out while waiting for proxy_protocol header

• Added a new feature to enable partial certificate chain validation for TLS listeners #10553.

  For details, please check out the listener.ssl.external.partial_chain in the listeners.conf config file.

• Added a new feature to enable client certificate extended key usage validation for TLS listeners #10669.

  For details, please check out the listener.ssl.external.verify_peer_ext_key_usage in the listeners.conf config file.

• Added the live_connections field in the HTTP API /api/v4/nodes response #10859.

  Previously, this interface had a connections field, which represented the number of active connections on the current node that had not expired. This means that even if the MQTT connection has been disconnected, as long as the client has a persistent session, it would still be counted in the connections field. The newly added live_connections field specifically counts the number of clients with MQTT connections that have not been disconnected.

• Added 3 random SQL functions to the rule engine #11113.

  • random(): Generates a random number between 0 and 1 (0.0 =< X < 1.0).
  • uuid_v4(): Generates a random UUID (version 4) string.
  • uuid_v4_no_hyphen(): Generates a random UUID (version 4) string without hyphens.

• Added numerical range validation (23-65535) for the mqtt.max_clientid_len configuration parameter #11096.

• Added a plugin emqx_gcp_device.

  It simplifies migration from Google IoT Core:

  • It allows import of Google IoT Core device configuration and authentication data.
  • Implements Google IoT Core compatible MQTT authentication.
  • Provides API endpoints for managing device configuration and authentication data.

• Added support for creating RabbitMQ actions with dynamic Routing Key.

  The "RabbitMQ Routing Key" parameter of RabbitMQ actions can now use dynamic variables in the ${key} format.

• Added default ports for DynamoDB resources.

  Previously, the "DynamoDB Server" parameter of DynamoDB resources required a URL with a specified port number, otherwise the resource creation would fail. Now, if the URL does not include a port number, the default value will be 80 (HTTP) or 443 (HTTPS).

Bug Fixes

• Fixed an issue where the rule engine was unable to access variables exported by FOREACH in the DO clause #10620.

  Given a payload: {"date": "2023-05-06", "array": ["a"]}, as well as the following SQL statement:

  FOREACH payload.date as date, payload.array as elem
  DO date, elem
  FROM "t/#"

  Prior to the fix, the date variable exported by FOREACH could not be accessed in the DO clause of the above SQL, resulting in the following output for the SQL statement: [{"elem": "a","date": "undefined"}]. After the fix, the output of the SQL statement is: [{"elem": "a","date": "2023-05-06"}]

• Fixed the issue where the cache of rules failed to update in certain cases #11072.

  Prior to the fix, after manually updating the rules, there could be instances where the cache update did not synchronize to certain nodes. This would result in inconsistent rule execution states across different nodes.

• Fixed an issue where the WebHook plugin failed to execute the on_client_connack hook #10710.

  See https://github.com/emqx/emqx/issues/10628 for more details.

• Fixed an issue related to reconnection of the authentication module.

  When starting EMQX, if the connection between the authentication module and the database is disconnected, the authentication module will periodically initiate reconnection. Prior to the fix, even if the module was manually disabled, EMQX would still periodically reconnect to the database. After the fix, reconnection attempts are made only when the module is enabled.

• Fixed an issue where the PgSQL authentication module lost Prepared Statements after reconnection.

  Prior to the fix, if the connection between the PgSQL authentication module and the database was disconnected and reconnected, authentication would fail due to the loss of Prepared Statements, and the following error log would be printed:

  2023-03-30T20:50:48.088416+08:00 [error] abc@124.79.220.151:58561 [Postgres] query '"auth_query"' failed: {error,error,<<"26000">>,invalid_sql_statement_name,<<"prepared statement \"auth_query\" does not exist">>,[...]}

• Fixed an issue where connection to Kafka failed after importing resources from version 4.4.9.

  Prior to the fix, when importing data from version 4.4.9 to 4.4.18, if the Kafka resource was not configured with a username and password (i.e. authentication mode was NONE), EMQX might incorrectly use PLAIN authentication mode to connect to Kafka after importing, resulting in authentication failure.

• Fixed the issue of EMQX docker container unable to integrate with Kafka using Kerberos authentication.

  Prior to the fix, the EMQX docker (alpine) image was missing two software packages, libsasl and cyrus-sasl-gssapiv2, which caused the Kerberos functionality to not work properly. The error log was as follows:

  2023-06-15T05:30:31.148811+00:00 [warning] ...,{connect_kafka_server_fail,[{<<"kafka-a:9092">>,{{not_loaded,[{module,sasl_auth},{line,212},{on_load_error_info,{error,{load_failed,"Failed to load NIF library: 'Error loading shared library libsasl2.so.3: No such file or directory (needed by /opt/emqx/lib/sasl_auth-2.0.1/priv/sasl_auth.so)'"}

• Fixed the data distribution logic of the RocketMQ action in the rule engine.

  Prior to the fix, in the scenario where EMQX sends data to a RocketMQ cluster in master-slave mode, if the RocketMQ cluster has multiple master nodes, regardless of whether the roundrobin or key_dispatch strategy is used, the messages will always be distributed to the first RocketMQ master node.

• Fixed the issue of module order changing after restarting or joining a cluster.

  Prior to the fix, after a node restarting or joining a cluster, the order of modules could change, which would cause the authentication chain order to change if multiple authentication modules were enabled.

• Fixed the issue of failing to import listener configurations from 4.4.7.

  Prior to the fix, if the JSON file contained configurations for "wss" or "wss" listeners, the import could fail due to an incompatible type of the fail_if_no_subprotocol configuration item, but without any error messages or logs.

• Fixed the issue of hot configurations not taking effect after a new node joins the cluster.

  Prior to the fix, when a node joined a cluster with hot configurations enabled, it could successfully replicate the hot configurations from the cluster, but the configurations did not take effect at runtime.

• Fix the issue that the WebSocket downlink message type of the OCPP gateway is incorrect.

  Prior to the fix, the WebSocket downlink message type of the OCPP gateway was binary, but it should be text.

• Fix issue when MQTT clients could not connect over TLS if the listener was configured to use TLS v1.3 only.

  The problem was that TLS connection was trying to use options incompatible with TLS v1.3.

• Fixed the issue of retainer module throwing errors after hot upgrade.

  After upgrading from old versions (e4.4.0 ~ e4.4.16) to e4.4.17 or e4.4.18, the retainer module might throw errors, causing retain messages to be unable to be sent properly. The error log is as follows:

  2023-05-17T01:48:44.515012+00:00 [error] mqtt_conti@62.93.210.184:54851 [Hooks] Failed to execute {fun emqx_retainer:on_session_subscribed/3,[]}: {error,badarg,[...]}

• Fixed the issue of error log appearing when testing the connectivity of RabbitMQ.

  Prior to the fix, when clicking the test button for RabbitMQ resources, the following error log would be printed (only the error log appeared, and the functionality was not affected):

  2023-06-02T05:59:16.025229+00:00 [error] Destroy Resource bridge_rabbit failed, ResId: <<"_probe_:6edc3a76">>, not_found

• Fixed the issue of creating multiple duplicate hot configuration modules when continuously clicking the Enable button on the Dashboard settings page.

4.4.18

Release Date: 2023-04-28

Enhancements

• Added plugin emqx_ocpp to support the OCPP 1.6-J protocol.

  OCPP (Open Charge Point Protocol) is a protocol used for communication between electric vehicle charging stations and central management systems. This plugin serves as an OCPP gateway for EMQX, enabling seamless integration between OCPP and MQTT protocols. It facilitates the smooth connection of charging stations to EMQX through OCPP over WebSocket.".

  To start the plugin, you can use the emqx_ctl plugins load emqx_ocpp command or EMQX Dashboard. Additionally, tools such as ocpp-go can be used to simulate charging points for message exchange testing.

• Improved the placeholder syntax of rule engine.

  The parameters of actions support using placeholder syntax to dynamically fill in the content of strings. The format of the placeholder syntax is ${key}.
  Before this improvement, the key in ${key} could only contain letters, numbers, and underscores. Now the key supports any UTF8 characters.

Bug Fixes

• Fixed the issue where required plugins were missing in data/load_plugins.

  Before this fix, if the data/load_plugins file was manually deleted and EMQX was restarted, three required plugins (emqx_schema_registry, emqx_eviction_agent, emqx_node_rebalance) would not be automatically enabled and would not be recorded in the newly generated data/load_plugins file.

4.4.17

Release Date: 2023-04-13

Enhancements

• When the listener enabled with Proxy Protocol receives a TCP port probe, no error logs will be printed anymore emqx/esockd#172.

  Before the fix, if the listener had enabled the proxy protocol (listener.tcp.external.proxy_protocol=on), but the connection was disconnected after the TCP handshake was completed and before the proxy information was received, the following error log would be printed:

  [error] supervisor: 'esockd_connection_sup - <0.3265.0>', errorContext: connection_shutdown, reason: {recv_proxy_info_error,tcp_closed}, offender:

  After the fix, no logs will be printed, but you can still view the error reason statistics through the emqx_ctl listeners command.

• Improved the error logs of the listener for file descriptor exhaustion emqx/esockd#173.

  Before the improvement, the log was:

  [error] Accept error on 0.0.0.0:1883: emfile

  After the improvement, the log became:

  [error] Accept error on 0.0.0.0:1883: EMFILE (Too many open files)

• Improved the performance of the rule engine when there are many rules #10283

  Before the improvement, when there were many rules, the rule engine would consume a lot of CPU time on rule queries and matching, becoming a performance bottleneck. In this optimization, by simply adding a cache to the rule list, the rule execution efficiency in this scenario was greatly improved. In our test, we created 700 rules that did not perform any actions (bound to the "do_nothing" debugging action) on a 32-core 32G virtual machine, and sent MQTT messages to EMQX at a rate of 1000 messages per second (that is, the rule trigger frequency was 700 * 1000 times per second). In the above scenario, the CPU usage of the optimized rule engine dropped to 55% ~ 60% of the previous level.

• Improve the alarm logs when importing data from old versions (4.2 or earlier).

  Before this change, if data was imported from versions 4.2 or earlier to version 4.4, the built-in authentication part of the data would be discarded due to the lack of authentication type, and the log description of the failure reason was not clear enough. After this change, the importing will fail, and the EMQX log will prompt the user to use the command line tool for data import and specify the authentication type:

  $ emqx_ctl data import <filename> --env '{"auth.mnesia.as":"username"}'

Bug Fixes

• Fixed the issue where Erlang distribution could not use TLS #9981.

  For more information on Erlang distribution, see here.

• Fixed the issue where MQTT bridging could not verify TLS certificates with wildcard domains on the peer side #10094.

• Fixed the issue where EMQX could not timely clear the information of disconnected MQTT connections when there were too many messages backlogged in the retainer. #10189.

  Before the fix, the emqx_retainer plugin and the EMQX connection information cleanup task shared a process pool. Therefore, if the process pool was blocked by a large number of retain message distribution tasks, many disconnected MQTT connection information would not be cleared in time. See #9409 for details. After the fix, the emqx_retainer plugin uses a separate process pool to avoid this problem.

• Fixed the issue where the path of the template file service-monitor.yaml in the Helm Chart was incorrect. #10229

• When upgrading from EMQX 4.3 to 4.4, EMQX will migrate the ACL table in the "built-in authentication" module upon restart.

  Before the fix, if data was migrated from version 4.3 to 4.4 by copying the data/mnesia/<node-name> directory, after the migration was completed, when viewing the "built-in authentication" module through the Dashboard, a 500 error would occur because the ACL table was not migrated to the new format. Note: This issue only occurs when the module is disabled, and users can manually enable the module to resolve it. After the fix, EMQX will attempt to migrate the ACL table upon restart after upgrading, thus avoiding this issue.

• Fix the issue of incorrect counting statistics for the IoTDB action.

  Before the fix, if all measurements were null, IoTDB would ignore them, not insert any data but return 200 OK, causing the increment of the successful sending count to be incorrect. After the fix, when all measurements are null, the IoTDB action will discard the request and count it as a sending failure.

• Fix the issue of rule creation failure when TDEngine SQL statements contain line breaks.

  Before the fix, TDEngine SQL statements could not contain line breaks. For example, when using the following statement as the SQL template parameter for the TDEngine action, rule creation would fail:

  INSERT INTO ${devid}
  USING
    tsdb.profit
  TAGS
    ('${custid}', '${devid}')
  VALUES (${ts}, ${value})

• Fix the issue of incorrect encoding of error messages returned by the HTTP API /load_rebalance/:node/start.

• Fix the process leak issue of the RocketMQ client in EMQX rocketmq-client-erl#24.

  EMQX's RocketMQ client periodically obtains node information from RocketMQ, checks whether the node information has been updated, and updates or adds producer processes based on the returned results. Before the fix, due to problems with the method of comparing node information, process leaks could occur in certain situations.

4.4.16

Release Date: 2023-03-10

This version update includes 4 enhancements and 7 fixes.

Enhancements

• Improve the logs for IoTDB resource. Before this change, if the user configured a different iotdb_version from the installed IoTDB version, sending messages to IoTDB will fail but it is hard to know the reason just from the log messages. After this change, we will print more readable logs to prompt the user that he may have configured a wrong iotdb_version.

• Don't print error logs when the offline-msg actions receive QoS0 messages.

• Change "EMQX" to "EMQX" from the outputs of CLIs and names of plugins.

Bug Fixes

• Start the emqx_schema_registry plugin automatically when release hot upgrade. The emqx_schema_registry is a necessary plugin when using rules to decode serialized binary data (e.g. Protobuf or Avro), we should ensure this plugin started in the EMQX enterprise.

• Fix the issue that the message_key parameter of the RocketMQ action does not work.

• Fix the rule failed when processing the decoded protobuf messages. Before this fix, if the protobuf schema contains oneof definitions, the rule may failed when trying to parse the decoded message to JSON string.

• Fix the issue that send JSON Object as Kafka Headers failed.

• Delete the temporary directories generated by resources and emqx-modules. Before this fix, sometimes the sub-directories in data/rules and data/modules cannot be cleaned even after the resources or emqx-module are deleted.

• Fix some problems in the descriptions of HStreamDB resource fields.

• Avoid changing the payload of MQTT messages when printing debug logs #10091. Before this fix, if EMQX receives a message with Payload "e\ne\nc\nc\n2\n\n\n", the log message will be as follows:

  2023-03-08T13:28:04.320622+08:00 [debug] mqttx_e34bd582@127.0.0.1:54020 [MQTT] RECV PUBLISH(Q1, R0, D0, Topic=t/1, PacketId=39467, Payload=e, e, c, c, 2, , , )

  This is the corresponding log message now:

  2023-03-08T14:26:50.935575+08:00 [debug] mqttx_e34bd582@127.0.0.1:54020 [MQTT] RECV PUBLISH(Q1, R0, D0, Topic=t/1, PacketId=39467, Payload=<<"e\ne\nc\nc\n2\n\n\n">>)

4.4.15

Release Date: 2023-03-03

This version update includes 16 enhancements and 20 fixes. Among the enhancements, there are new exciting new features worth highlighting:

• Upgrade the MongoDB client library of EMQX to support MongoDB 5.1 and above.
• Dashboard supports the proxy protocol of HAProxy.
• Release the Ubuntu 22.04 installation package.
• Support Kafka headers in rule engine.
• Support storing data to IoTDB using rule-engine.

Enhancements

• Support Kafka headers in rule engine.

• Support storing data to IoTDB using rule-engine.

• The JT/T 808 compatible non-standard location reporting messages. When a user uses a reserved ID to report a location, EMQX will pass it through in Base64 format instead of disconnecting the client.

• Only create EMQX modules locally when the emqx_modules application is started. Before this change, we RPC to all the nodes to create/recreate modules when emqx_modules application get started, so finally we created modules N^2 times on all the nodes (N times on each node).

• Improve the log message when the DynamoDB action cannot find the hash_key or range_key.

• HStreamDB driver update to support HStreamDB ~> 0.12.0.

• The plugin schema_registry will be enabled by default as an optional feature of rule_engine.

• Add TLS connections support for HStreamDB action.

• The MongoDB library has been upgraded to support MongoDB version 5.1 and greater.

• Support proxy protocol of HAProxy for dashboard API 9803.

• Added Ubuntu 22.04 package release #9831.

• Improve the integration of the banned and the delayed feature #9790. Now when publishing a delayed message will check first if its source client is banned, if true, this publish will be ignored.

• Security enhancement for retained messages #9790. The retained messages will not be published if the publisher client is banned.

• Now the corresponding session will be kicked when client is banned by clientid #9904.

• Add more debug logs for authentication and ACL #9943.

• Expose the stats live_connections.count and live_connections.max to Prometheus #9929.

Bug Fixes

• Fixed tlsv1.3 is missing from Module(Stomp Gateway, GB/T 32960 Gateway, JT/T808 Gateway, Extension Protocol, TCP Gateway, MQTT Subscriber) tls_versions tab.

• Fix the problem of sending offline messages to clients in reverse order when using Redis offline message feature.

• Fix the emqx-modules are disabled if their initialization failed after EMQX is restarted.

• Fix some issues in descriptions of the actions and resources.

• Fix the issue that Oracle resources cannot get connected automatically after release hot upgrade.

• Fix the issue that produce messages to RocketMQ cluster using rule-engine failed.

• Returning a failure when creating an existing listener in a cluster using the API.

• Delete the files directory when resources/modules/schema_registry were deleted to avoid files leaking.

• Fixed an error when forward MQTT messages with User-Property using the republish action #9942.

• Fix some issues in descriptions of the actions, resources and emqx-modules #9931.

• Fix there's no error logs when query the JWKS server failed #9931.

• The returned client lists of HTTP query GET /api/v4/clients?_page=2&_limit=20 to different nodes might be inconsistent #9926.

• Fix the problem that new MQTT TLS connections failed to establish after release hot upgrade #9810. For more detailed information please see: emqx/esockd#170.

• Fix a problem in the log message format of MQTT packets #9858. Before this fix, a comma was missing between the flags (DUP) of the fixed header and the fields (ClientId) of the variable header:

  2023-01-29T13:40:36.567692+08:00 [debug] 127.0.0.1:50393 [MQTT] RECV CONNECT(Q0, R0, D0ClientId=test_client, ... Password=undefined)

• Avoid crash logs in CoAP gateway when receiving liveness checking packets from Load Balancer #9869.

• Fix the exclusive topics aren't removed when the session has already been cleaned #9868.

• Fix the EMQX reports {case_clause,{error,closed}} error log message when WebSocket connections interrupted emqx/cowboy#8.

• Fix sometimes the rules cannot be enabled automatically after EMQX is restarted #9911.

• Fix the {badarg,[{ets,lookup,[gproc,{shared, ... error logs during shutdown #9919.

• Fix crash when updating a client's keepalive via the HTTP API if it connects with keepalive disabled #9933.

4.4.14

Release Date: 2023-01-06

Enhancements

• Add a password complexity requirement when adding or modifying Dashboard users via the API. Now passwords must contain at least 2 of alphabetic, numeric and special characters, and must be 8 to 64 characters long.

Bug Fixes

• Fix the problem that adding or importing Dashboard users via the API fails to add complex passwords due to incorrect checksum of the passwords.

• Fix load bootstrap_app_file's apps is not sync when reboot.

4.4.13

Release Date: 2023-01-03

Bug Fixes

• Fix an issue where testing the GCP PubSub could leak memory, and an issue where its JWT token would fail to refresh a second time. #9640

4.4.12

Release Date: 2022-12-29

This version comes with an exciting new feature: cluster load rebalance. The newly introduced CLI command emqx_ctl rebalance provides support of the below two common scenarios:

• Newly joined or restarted nodes may stay under-loaded for along time if the clients are mostly long-lived connections
• For maintenance, shutting down a node will cause all connected connections to reconnect around the same time, increasing the chance to overload the cluster. Also the non-clean sessions in this node will be lost.

Now it’s possible to issue the rebalance command to move some of the connections the under-loaded nodes. With the --evacuation option, we can also move all the connected MQTT clients off the node before stopping the service.

Enhancements

• Added topic validation for emqx_mod_rewrite. The dest topics contains wildcards are not allowed to publish.

• TDEngine resource support HTTP response formats of both TDEngine 2.x and 3.x emqx/tdengine-client-erl#7. The HTTP response of TDEngine 2.x uses the status field to represent the success or failure, while TDEngine 3.x uses the code field instead.

• Support batch sending messages to TDEngine SubTables.

• The offline message clickhouse action prints an info level log: Destroyed .. Successfully when enabling a rule.

• Now the rules can be created even though the corresponding resources are not ready. Before this change, one cannot create rules without getting the resources connected. We made it possible in this change, but the newly created rule will be in disabled state.

• Avoid delete offline message twice. EMQX while delete offline message in external database when subscriber send a PUBACK or PUBREC packet. But a message with retain = true will be stored twice (in retainer and external database) in case retain message and offline message are used in same time. The reduplicated PUBACK and PUBREC will trigger deleted action twice. And the action-metrics will also increase caused by Rule-SQL execution succeed. In most cases this does not generate any exceptions or errors, and only a few databases will report that the message to be deleted does not exist on the second delete. This change will avoid redundant offline message deletion operations.

• Users can define the externalTrafficPolicy of service in EMQX Enterprise Helm Chart.

• When dashboard creates a new user, the password format is ^[A-Za-z0-9]+[A-Za-z0-9-_]*$.

Bug Fixes

• After a reconnect, the unacknowledged QoS1/QoS2 messages in non-clean session were not retransmitted periodically as before the reconnect. The configuration zone.<zone-name>.retry_interval specifies the retransmission interval of unacknowledged QoS1/QoS2 messages (defaults to 30s). Prior to this fix, unacknowledged messages buffered in the session are re-sent only once after session take-over, but not retried at configured interval.

• The expired 'awaiting_rel' queue is not cleared after persistent session MQTT client disconnected. Before this change, if the 'awaiting_rel' queue is full when the MQTT client reconnect to the broker and publish a QoS2 message, the client will get disconnected by the broker with reason code RC_RECEIVE_MAXIMUM_EXCEEDED(0x93), even if the packet IDs in the 'awaiting_rel' queue have already expired.

• Authentication for RocketMQ resource not working. In this change we moved the configuration fields access_key, secret_key and security_token from the data_to_rocket action to the bridge_rocket resource. And we also added a new field namespace for RocketMQ services in Aliyun cloud.

• Added validation for Kafka action parameters, Segment Bytes should not be greater than Max Bytes.

• Added validation for Pulsar action parameters, Segment Bytes should not be greater than Max Bytes.

• Fix the "ORA-01000: maximum open cursors exceeded" problem when sending data via the emqx oracle resource.

• Fixed EMQX Enterprise Helm Chart deployment error.

  • Fixed the Discovery error: no such service error occurred during helm chart deployment, resulting in an abnormal discovery of cluster nodes.
  • Fixed EMQX Enterprise Helm Chart can not set JSON type value for EMQX Enterprise configuration items.

• Fixed an issue where the configuration would not be reloaded on all nodes in a cluster after importing a backup configuration.

• Fixed an issue where the HTTP API would fail to download a backup configuration file when downloading it from a node where it does not reside in.

• Add the SNI field for SSL connection configuration of Kafka resource.

• Fixed the issue that the MongoDB resource connection process was slow when authentication was enabled.

• Fixed the issue that after the release hot upgrade, EMQX occasionally alarms resources down, and the alarms could not be automatically cleared.

• Fix connection statistics in the dashboard: mark evacuated clients as disconnected before they can reconnect.

4.4.11

Release Date: 2022-11-26

This release included 23 enhancements and 21 bug fixes. Among the enhancements, there are new exciting new features worth highlighting.

• Google PubSub integration as a Rule-Engine data bridge.
• OCSP (Online Certificate Status Protocol) Stapling.
• CRL (Certificate Revocation List) cache.
• Pulsar data bridge supports data buffering.
• OTP upgrade from 24.1.5-3 to 24.3.4.2-1.
• Customizable client aliases to make it easier to when creating customized authentication and authorization.

It is possible to hot-upgrade from the older version e4.4 to this version. Please note though, in order to start making use of the new features such as OCSP Stapling, and CRL cache, a node restart (and configuration change) is required.

Enhancements

• Upgraded Pulsar client to 0.7.0. Now it's possible to buffer messages to be produced to Pulsar while EMQX has no connection to the Pulsar broker. Such messages will be retained for a configurable amount of time.

  Also, credentials such as basic auth and JWT tokens used for Pulsar authentication will be censored out when a crash happens, thus avoiding secret leakage to logs.

  Note: if an older EMQX version is upgraded to a version containing this update, and then downgraded back to the previous old version, there's a risk that some messages that were sent in a sync manner might be sent but regarded as a timeout error, which in turn causes such clients to be disconnected.

• Added hot-configuration support for OCSP stapling and CRL checking/caching.

• Added a new rule engine bridge and corresponding rule action for GCP PubSub.

• Support to use placeholders like ${var} in the Collection field of Rule-Engine's MongoDB actions

• Add a format check to the host field of the InfluxDB resource in Rule-Engine. The host field should be an ip/domain without scheme and port.

• OTP upgrade from 24.1.5-3 to 24.3.4.2-1 #9265. Change highlights:

  • Erlang/OTP SSL library vulnerability fix
  • Added support for OCSP (Online Certificate Status Protocol) Stapling
  • Added CRL (Certificate Revocation List) cache auto refresh

• Added support for OCSP stapling and CRL caching #9297.

• Added support for specifying custom modules for adding clientid and common name aliases #9297. Now you can implement a simple callback to enrich clients with aliases, and then use the aliases in the authentication and authorization (ACL) rules' place holders (%cida for clientid alias and %cna for username alias).

• Added support for specifying custom modules for custom authentication #9297. To support simple authentication rules, it is no longer necessary to implement a full-blown plugin.

• Added a JWT management for Rule-Engine, for creating and refreshing JWT tokens in rule engine actions #9241. This feature is so far only used in EMQX Enterprise Google PubSub integration. Can be used as webhook integration's JWT authentication against the webhook service endpoint.

• Make sure listener's tls_versions config value is one or more of tlsv1, tlsv1.1, tlsv1.2, tlsv1.3 #9260.

• Remove useless information from the dashboard listener failure log #9260.

• We now trigger the 'message.acked' hook after the CoAP gateway sends a message to the device and receives the ACK from the device #9264. With this change, the CoAP gateway can be combined with the offline message caching function (in the emqx enterprise), so that CoAP devices are able to read the missed messages from the database when it is online again.

• Support to use placeholders like ${var} in the HTTP Headers of Rule-Engine's Webhook actions #9239.

• Asynchronously refresh the resources and rules during emqx boot-up #9199. This is to avoid slowing down the boot if some resources spend long time establishing the connection.

• Add a warning log if the ACL check failed for subscription #9124. This is to make the ACL deny logging for subscription behave the same as for publish.

• JWT ACL claim supports all action to imply the rules applie to both pub and sub #9044.

• Added a log censor to avoid logging sensitive data #9189. If the data to be logged is a map or key-value list which contains sensitive key words such as password, the value is obfuscated as ******.

• Enhanced log security in ACL modules, sensitive data will be obscured #9242.

• Add management.bootstrap_apps_file configuration to bulk import default app/secret when EMQX initializes the database #9273.

• Added two new configs for deterministic order of authentication and ACL checks #9283. The two new global config names are auth_order and acl_order. When multiple ACL or auth plugins (or modules) are enabled, without this config, the order (in which each backend is queried) is determined by the start/restart order of the plugin (or module). Meaning, if a plugin (or module) is restarted after initial boot, it may get ordered to the end of the list. With this config, you may set the order with a comma-speapated ACL or auth plugin names (or aliases). For example: acl_order = jwt,http, this will make sure jwt is always checked before http, meaning if JWT is not found (or no acl cliam) for a client, then the ACL check will fallback to use the HTTP backend.

• Added configurations to enable more client.disconnected events (and counter bumps) #9267. Prior to this change, the client.disconnected event (and counter bump) is triggered when a client performs a 'normal' disconnect, or is 'kicked' by system admin, but NOT triggered when a stale connection had to be 'discarded' (for clean session) or 'takeovered' (for non-clean session) by new connection. Now it is possible to set configs broker.client_disconnect_discarded and broker.client_disconnect_takeovered to on to enable the event in these scenarios.

• For Rule-Engine resource creation failure, delay before the first retry #9313. Prior to this change, the retry delay was added after the retry failure.

Bug Fixes

• Fix the default authentication mechanism of Kafka resource changed to NONE from PLAIN when upgrading emqx from e4.4.5 and older versions.

• Fix an upgrade issue for JWT authentication plugin. When upgrading from e4.4.3 or earlier, an EMQX internal resource which holds the keys will have to be restarted, during the restart, clients may fail to be authenticated.

• Fixed the option to choose the reset_by_subscriber offset reset policy in Kafka Consumer.

• Added the missing tlsv1.3 option to tls_versions in hot-config.

• Made Rule-Engine able to connect SQL server when its listening port is not the default (1433).

• Make sure Schema-Registry API supports Percent-encoding name in HTTP request URI. Note that the name in POST /api/v4/schemas request body should not be percent-encoded as it's a JSON field value.

• Fix an upgrade issue for JWT authentication plugin. When upgrading from e4.3.9 or earlier, an EMQX internal resource which holds the keys will have to be restarted, during the restart, clients may fail to be authenticated.

• Fix get trace list crash when trace not initialize. #9156

• Fix create trace sometime failed by end_at time has already passed. #9156

• Fix that after uploading a backup file with an non-ASCII filename, HTTP API GET /data/export fails with status code 500 #9224.

• Improve the display of rule's 'Maximum Speed' counter to only reserve 2 decimal places #9185. This is to avoid displaying floats like 0.30000000000000004 on the dashboard.

• Fix the issue that emqx prints too many error logs when connecting to mongodb but auth failed #9184.

• Fix that after receiving publish in idle mode the emqx-sn gateway may panic #9024.

• "Pause due to rate limit" log level demoted from warning to notice #9134.

• Restore old emqx_auth_jwt module API, so the hook callback functions registered in older version will not be invalidated after hot-upgrade #9144.

• Fixed the response status code for the /status endpoint #9210. Before the fix, it always returned 200 even if the EMQX application was not running. Now it returns 503 in that case.

• Fix message delivery related event encoding #9226 For Rule-Engine's input events like $events/message_delivered, and $events/message_dropped, if the message was delivered to a shared-subscription, the encoding (to JSON) of the event will fail. Affected versions: v4.3.21, v4.4.10, e4.3.16 and e4.4.10.

• Make sure Rule-Engine API supports Percent-encoding rule_id and resource_id in HTTP request path #9190. Note that the id in POST /api/v4/rules should be literals (not encoded) when creating a rule or resource. See docs Create Rule Create Resource.

• Calling 'DELETE /alarms/deactivated' now deletes deactived alarms on all nodes, including remote nodes, not just the local node #9280.

• When republishing messages or bridge messages to other brokers, check the validity of the topic and make sure it does not have topic wildcards #9291.

• Disable authorization for api/v4/emqx_prometheus endpoint on management api listener (default 8081) #9294.

4.4.10

Release Date: 2022-10-14

Enhancements

• Added more Kafka action parameter checks

  • TCP send buffer size and max batch size parameters are not allowed to be left blank from the configration UI.
  • The combination of "Produce Strategy" set to 'key_dispatch' and the "Key" set to "none" is now not allowed, the dashboard will get an error with text like: "with strategy set to 'key_dispatch', key is not allowed to be 'none'"

• TLS listener memory usage optimization #9005. New config listener.ssl.$NAME.hibernate_after to hibernate TLS connection process after idling. Hibernation can reduce RAM usage significantly, but may cost more CPU. This configuration is by default disabled. Our preliminary test shows a 50% of RAM usage decline when configured to '5s'.

• TLS listener default buffer size to 4KB #9007. Eliminate uncertainty that the buffer size is set by OS default.

• Disable authorization for api/v4/emqx_prometheus endpoint #8955.

• Added a test to prevent a last will testament message to be published when a client is denied connection #8894.

• More rigorous checking of flapping to improve stability of the system #9045. Previsouly only normal disconnects are counted, now the connection rejections (e.g. authentication failure) is also included. Find more about flapping detection in EMQX document

• QoS1 and QoS2 messages in session's buffer are re-dispatched to other members in the group when the session terminates #9094. to prevent sessions from buffering messages, however this acknowledgement costs extra resources.

• Fix delayed publish timing inaccuracy caused by OS time change #8908.

Bug Fixes

• Fix load_modules reset after new node joins the cluster. Prior to this fix, if load_modules for a cluster has been changed, adding a new node to the cluster with default modules would cause the other nodes to reset to default too. In this fix, the node which is going to join the cluster will copy the loaded_modules from the oldest node in the cluster.

• Fix getting subscriptions from backends successfully with QoS values out of range [0, 2]. Before this change, when we add subscriptions for clients from backends like Redis or MySQL, we won't validate the QoS. For example if the QoS is an integer -1, the topic was still subscribed successfully with QoS -1, if we send a message to this topic, then an error will occur and the MQTT connection will crash. After this change QoS will be clamped into range [0, 2].

• Fix Rule-Engine increased 'success' counter when get subscriptions from Redis failed (due to query Redis timeout).

• Fix Rule-Engine increased 'success' counter when saving offline messages with QoS = 0. We don't allow saving offline messages to backends with QoS = 0, so we need to increase the 'failed' counter instead of the 'success' counter in this case.

• Fix the verify field is missing from the SSL settings of redis-cluster and redis-sentinel resources.

• Fixed Redis resource liveness problem issue. Prior to this fix, the resource is considered alive when connection can be established. The fix is to perform a PING query to make sure the service is alive.

• Fix the redis-cluster resource prints too many error logs when redis servers are not avaliable.

• Fixed an internal Redis resource ID clashing. This clashing may cause resources in use getting deleted when deleting another resource.

• Mask secret/password in the resource/module creation UI.

• Fix HTTP client library to handle SSL socket passive signal #9145.

• Hide redis password in error logs #9071. More changes in redis client included in this release:

  • Improve redis connection error logging eredis#19. Also added support for eredis to accept an anonymous function as password instead of passing around plaintext args which may get dumpped to crash logs (hard to predict where). This change also added format_status callback for gen_server states which hold plaintext password so the process termination log and sys:get_status will print '******' instead of the password to console.
  • Avoid pool name clashing eredis_cluster#22. Same format_status callback is added here too for gen_servers which hold password in their state.

• Fix shared subscription message re-dispatches #9094.

  • When discarding QoS 2 inflight messages, there were excessive logs
  • For wildcard deliveries, the re-dispatch used the wrong topic (the publishing topic, but not the subscribing topic), caused messages to be lost when dispatching.

• Fix shared subscription group member unsubscribe issue when 'sticky' strategy is used. Prior to this fix, if a previously picked member unsubscribes from the group (without reconnect) the message is still dispatched to it. This issue only occurs when unsubscribe with the session kept. Fixed in #9119

• Fix shared subscription 'sticky' strategy when there is no local subscriptions at all. Prior to this change, it may take a few rounds to randomly pick group members until a local subscriber is hit (and then start sticking to it). After this fix, it will start sticking to whichever randomly picked member even when it is a subscriber from another node in the cluster. Fixed in #9122

• Fix rule engine fallback actions metrics reset #9125.

4.4.9

Release Date: 2022-09-17

Enhancements

• The exp, nbf and iat claims in JWT authentication support non-integer timestamps

Bug Fixes

• Fix rule engine update behaviour which may initialize actions for disabled rules
• Fix inaccurate delayed publish due to OS time changes
• Fix the issue that the IP address bound to the Dashboard listener did not take effect
• Fix the issue that shared subscriptions might get stuck in an infinite loop when shared_dispatch_ack_enabled is set to true
• Fix the issue that the rule engine SQL crashes when subject matching null values

4.4.8

Release Date: 2022-08-29

Enhancements

• Add GET /trace/:name/detail API to view log trace file information
• Improve the log when LwM2M packet parsing fails
• Improve the rule engine error log, the log will contain the rule ID when the action execution fails
• Improve log when loaded_modules and loaded_plugins files do not exist
• Add a guide for changing the default password on Dashboard
• Improved import performance for Protobuf Schema files

Bug Fixes

• Fix client.disconnected event not trigger in some cases
• Fix the issue that the JWK authentication module could not be started later when the JWKS service was not ready in time
• Fix the issue that setting the listener port via an environment variable would prevent either listener from being stopped
• Fix the issue that the built-in database authentication did not distinguish the pagination statistics of the authentication data of the client ID and username
• Fix the issue that the module status would be reset after EMQX restarts after hot upgrade
• Fix Redis driver process leak problem
• Fix rule engine MQTT bridge to AWS IOT connection timeout issue
• Fix GET /listener request crashing when listener is not ready
• Fix the issue that the comparison between any variable and null value in the rule engine SQL always returns false after e4.4.1
• Fix the issue that when the execution priority of ExHook is higher than that of the rule engine, the topic filtered by the ExHook Message Hook will not trigger the rule engine
• Fix the issue that the write request of TDEngine may fail because the peer end closes the network connection
• Fix the issue that the configuration of the MQTT-SN module other than the listener would not take effect
• Fix the issue that the ExHook management process was forcibly killed due to the supervisor shutdown timeout
• Fix the issue that the Client ID parameter in ExProto client.connect hook is not defined
• Fix ExProto not triggering disconnect event when client is kicked

4.4.7

Release Date: 2022-08-11

Important Changes

• As of version 4.4.7, we will no longer provide packages for macOS 10

Enhancements

• Allows the connection process to be configured to be garbage collected after the TLS handshake is complete to reduce memory footprint, which can reduce memory consumption by about 35% per SSL connection, but increases CPU consumption accordingly
• Allows configuring the log level of the TLS handshake log to view the detailed handshake process

Bug Fixes

• Fix the issue that EMQX could not be started when deployed through Helm Chart after unmounting the loaded_modules file in ConfigMap

4.4.6

Release Date: 2022-07-29

Enhancement

• Rules engine supports RocketMQ with ACL enabled
• Supports searching and paging of rules in rule engine
• Kafka in Rules Engine now supports SASL/SCRAM authentication and SASL/GSSAPI authentication. Note that the cyrus-sasl-gssapi dependency needs to be installed before using SASL/GSSAPI authentication
• Provides CLI ./bin/emqx check_conf to actively check if the configuration is correct
• Optimize the write performance of TDEngine in the rule engine
• Support for clearing historical alarms on Dashboard
• Optimizing Shared Subscription Performance
• Add db_name field to the action of rule engine writing data to TDEngine to improve support for super table

Bug Fixes

• Fix the issue that the action count is wrong when the rule engine writes to TDEngine
• Fix the issue that the process pool size setting does not take effect when the rule engine writes to HStreamDB
• Fix the issue that an error was reported when querying the subscription list after the GB/T 32960 plugin was enabled
• Fix the issue that incompatible configuration items when restoring a 4.2 backup to 4.4 with hot configuration enabled
• Fix the issue that once the old version of EMQX is uninstalled after hot upgrade, EMQX will not be able to start again
• Fix the issue that the keep-alive check for UDP clients in the Multilingual Protocol Extension was incorrect, causing clients not to expire
• Fix the issue that the client information in the Multilingual Protocol Extension was not updated in time
• Fix the issue that the license update does not take effect when running after hot upgrade to e4.4.4 and later versions
• Fix the issue that when the client specified Clean Session as false to reconnect, the shared subscription message in the flight window would be re-dispatched to the old session process
• Fix the issue that the new node did not use the cluster license after joining the cluster
• Fix the issue that the emqx_lua_hook plugin cannot cancel the message publishing

4.4.5

Release Date: 2022-06-30

Enhancement

• Rule engine supports persisting data to HStreamDB
• QoS and Retain flag in rule engine's message republish actions can now use placeholders
• Supports exclusive subscriptions, that is, only one subscriber is allowed for a topic
• Support one-click update of cluster license through CLI
• Dashboard and management API's HTTPS listeners can now use password-protected private key files, providing key_password configuration item
• Support for placeholders %u and %c in topic rewrite rules
• Support setting MQTT 5.0 properties in the API request for message publishing, such as message expiry interval, response topic, etc.
• Optimize the UI when creating rule engine resources, such as folding some uncommon options, etc.
• Opened 4 TCP-related configuration items: KeepAlive, TCP_NODELAY, SO_RCVBUF and SO_SNDBUF for the underlying gRPC connection of ExHook

Bug Fixes

• Fix the issue of inaccurate memory calculation in Linux OS, and calculate the memory usage of the current OS instead of the memory usage of EMQX
• Fix the issue that the old disconnect event of ExHook would be triggered later than the new connect event when the client reconnects
• Improve the JWT authentication module's judgment logic for startup status in a cluster environment
• Extend the timeout of DynamoDB resource status query of rule engine to avoid the problem that some overseas resources may not be available
• Fix the issue that the timestamp is not updated when the PostgreSQL data storage plugin persists messages and updates message consumption
• Fix the issue that the rules engine's Tablestore, Lindorm and InfluxDB resources did not check connection status when creating
• Fix rule engine not checking connection status when creating Tablestore, Lindorm and InfluxDB resources
• Fix rule engine not updating metrics correctly when writing to TDEngine resource fails
• Fix the issue that the Cassandra message store plugin persisted retained messages to multiple tables, causing duplicate messages
• Fix the issue that Kafka resources exported from versions prior to 4.3.0 (only when the Produce policy is set to first_key_dispatch) could not be imported into 4.3.0 and later
• Fix the issue that the execution order of topic rewriting and delayed publish is not fixed, now it is fixed to execute topic rewriting first
• Improve the null value handling when rule engine persists data to InfluxDB and Tablestore, now null values will not be written
• Fix the issue that rule engine could not encode MQTT 5.0 user properties
• Fix the issue that the count of connack.auth_error is inaccurate when the client uses a protocol version below MQTT v5.0 to access
• Fix the issue that the UDP listeners of LwM2M and CoAP gateways could not bind to the specified network interface
• Fix Dashboard not starting after removing the default Dashboard user in the configuration file
• Fix client.subscribe hook not being able to reject subscriptions
• If the placeholder in the ACL rule is not replaced, the client's publish or subscribe operation will be rejected
• Fix the issue that TLS was enabled but no TLS connection was actually established with Pulsar

4.4.4

Release Date: 2022-06-01

Enhancement

• Add more time transformation functions to the SQL of rule engine
• Add the float2str/2 function to the SQL of rule engine to support specifying the output precision of floating point numbers
• Rule engine supports message persistence to Alibaba TableStore
• Rule engine supports connecting to Pulsar using Basic and JWT authentication
• Add service_name option to Oracle resource of rule engine to support Oracle Database RAC
• Support for using JWT for authorization, now MQTT clients can authorize using specific claims that include a pub-sub whitelist
• Improved authentication related metrics to make it easier to understand, now client.authenticate = client.auth.success + client.auth.failure
• Support binding the listener of the REST API to a specified network interface
• Upload license will be automatically synchronized to the entire cluster, no need for each node to upload separately, provide HTTP API
• Support multi-condition query and fuzzy query for user data in authentication and authorization using built-in database as data source
• Supports querying clients using the length of the message queue and the number of dropped messages as conditions
• Support to configure the log time format to be compatible with the time format in older versions
• When use_username_as_clientid is configured to true and the client connects without specifying a username, the connection is now rejected with a reason code 0x85
• Full randomisation of app secrets (previously partially randomised)
• When using CLI for backup and recovery, it is no longer required that the backup file must be located in the backup folder of the EMQX data directory
• Hot upgrades between incompatible versions will now be rejected
• Allow white spaces in EMQX's installation path
• Boot script fail fast on invalid node name (improve error message readability)

Bug Fixes

• Fix the issue that the client could not get the message after going online when using the PostgreSQL offline message plugin
• Fix the issue that the rules engine could not successfully establish a TLS connection with Pulsar in some cases
• Fix the issue that rule engine's SQL function hexstr_to_bin/1 could not handle half-byte
• Fix the issue that the alarm was not cleared when the rule engine resource was deleted
• Fix Dashboard HTTPS listener's verify option not taking effect
• Fix the issue that messages were lost when the peer session was terminated during the delivery of QoS 1 messages through shared subscriptions
• Fix the issue that when the log tracer encounters large packets, the heap size grows too fast and triggers the policy of forcibly closeing the connection process
• Fix the issue that the relevant hooks were not properly uninstalled when the module was disabled, resulting in abnormal functions
• Fix the issue that the MQTT-SN client would be disconnected when retransmitting QoS 2 messages
• Fix the issue that modules that were turned off in the backup file would be automatically enabled after restoring the backup
• Fix the issue that the subscriber's connection was disconnected due to the wrong user properties type in the message publishing API api/v4/mqtt/publish
• Fix DynamoDB driver not adapting to OTP 24, causing it to be unavailable
• Fix the issue that some authentication algorithms were unavailable due to the PostgreSQL driver not adapting to OTP 24
• Fix the issue that the returned results did not match the query conditions when querying subscriptions with multiple conditions
• Fix rule engine resource connection test not working
• Fix multiple Dashboard display issues

4.4.3

Release Date: 2022-04-18

Enhancement

• Schema registry now supports decoding arbitrary binary payloads to JSON data using gRPC services
• Support for connecting to Pulsar using TLS
• Add mongo_date function for SQL in rule engine, which supports saving timestamps as MongoDB Date objects
• Rule engine supports resetting metrics of the specified rule
• Add connection confirmation and authorization completion events to the rule engine
• Rule engine supports copying rule for fast reuse
• SQL in rule engine supports zip, gzip and other compression and decompression functions
• Improve the error message when rule engine fails to parse payload
• Improve the connection test for some resources in rule engine
• Support setting execution priority for ExHook
• ExHook callback interface adds a Protobuf field RequestMeta meta to return the EMQX cluster name
• Support local policy for shared subscriptions, which will preferentially send messages to shared subscribers under the node where messages flow in. In some scenarios, the efficiency of shared message scheduling will be improved, especially when the MQTT bridge is configured as a shared subscription
• RSA-PSK-AES256-GCM-SHA384, RSA-PSK-AES256-CBC-SHA384, RSA-PSK-AES128-GCM-SHA256 and RSA-PSK-AES128-CBC- SHA256 four new TLS PSK cipher suites are supported, removing two insecure cipher suites PSK-3DES-EDE-CBC-SHA and PSK-RC4-SHA from the default configuration
• Diagnostic logging for wait_for_table of mnesia
  • Prints check points of mnesia internal stats
  • Prints check points of per table loading stats, help to locate the problem of long table loading time.
• Subscribing to an empty topic is prohibited in strict mode
• Generate default files when loaded_modules and loaded_plugins files do not exist

Bug Fixes

• Fix the issue that the TLS configuration item server_name_indication is set to disable and does not take effect
• Fix potential process leak issue in MongoDB driver
• Fix the issue that the password of the default Dashboard user modified via the CLI command would be reset after the node leaves the cluster
• Silence grep and sed warnings in docker-entrypoint.sh
• Fix the backup file cannot be deleted and downloaded when the API path contains ISO8859-1 escape characters
• Fix the issue that the Redis driver would crash when DNS resolution failed, etc
• Fix the issue that the MQTT Bridge plugin cannot be started when only the subscription topic is configured but QoS is not configured
• When creating a rule, if a rule with the same ID already exists, the rules engine will now report an error instead of replacing the existing rule
• Fix the issue that the HTTP driver process pool may not be deleted
• Fix the issue that the module parameters could not be updated again after failing to update
• Fix the incorrect type of some fields in the GB/T 32960 access gateway module in Dashboard
• Fix the issue that the configuration of Bridge resources such as Kafka and Pulsar could not be updated
• Fix the issue that JT/T 808 client authentication fails when anonymous authentication is enabled

4.4.2

Release Date: 2022-04-01

Important changes

• For Docker images, the configuration directory /opt/emqx/etc has been removed from the VOLUME list, making it easier for users to rebuild images with changed configurations.
• CentOS 7 Erlang runtime rebuilt on OpenSSL-1.1.1n (previously 1.0), prior to v4.3.13, EMQX will fail to handshake and trigger malformed_handshake_data exception when clients use certain cipher suites.
• CentOS 8 Erlang runtime system rebuilt on RockyLinux 8. centos8 will remain in the package name for backward compatibility.

Enhancement

• Add Pulsar proxy support for rule engine bridging data to Pulsar.
• Add OOM protection for Kafka producers.
• Add command line interface emqx_ctl pem_cache clean to allow forcibly clear x509 certificate cache to reload immediately after certificate file update.
• Refactored ExProto so that anonymous clients can also be displayed on Dashboard.
• Topic configuration items in bridges can now use ${node} placeholders.
• Add validation of UTF-8 strings in MQTT packets in strict mode. When set to true, invalid UTF-8 strings will cause the client to disconnect.
• MQTT-SN gateway supports initiative to synchronize registered topics after session resumed.
• Improve the writing precision of rule engine floating point data from 10 decimal places to 17 decimal places.
• EMQX will prompt how to modify the initial password of Dashboard at startup.

Bug Fixes

• Fix MQTT Subscriber module not being able to use two-way SSL connection.
• Fix the issue that PSKFile module failed to start.
• Fix the issue that Kafka Consumer Group module could not process binary data.
• Fix the issue that Log Trace could not be stopped.
• Fix the issue that the alternate action could not be triggered when the action of the rule engine persisting data to Oracle and Lindorm (only synchronous operation) failed to execute.
• Fix an issue where rule engine data persistence to Oracle failed but the success count still increased.
• Fix the issue that some zone configurations could not be cleared.
• Fix an issue where changes to some monitoring and alarm configurations were invalid after restarting.
• Fix the issue that Schema Registry is not available in the cluster environment.
• Fix the issue that the LwM2M client list query API returned incorrect data in a cluster environment, which resulted in the inability to access the LwM2M gateway module management page.
• Fix the issue that the JT/T 808 location report frame was parsed incorrectly.
• Fix the issue that the el8 installation package cannot be started on Amazon Linux 2022, the error content is errno=13 Permission denied.
• Fix an issue where the client could not reconnect if the connection process was blocked in some cases. Now waiting for more than 15 seconds without a response will force the old connection process to be closed.
• Fix the issue of query resource request timeout when rule engine resource is unavailable.
• Fix the issue of {error, eexist} error when re-run after hot upgrade failed.
• Fix an issue where publishing to a non-existing topic alias would crash the connection.
• Fix 500 error when querying lwm2m client list on another node via HTTP API.
• Fix HTTP API for subscribing topics crashes when invalid QoS are passed in.
• Fix the issue that the connection count was not updated because the related resources were not released when the connection process accessed through the ExProto exited abnormally.
• Fix an issue where the value of server_keepalive configuration item would be incorrectly applied to MQTT v3.1.1 clients.
• Fix Stomp client not firing $event/client_connection event messages.
• Fix the issue that the system memory alarm was incorrectly activated when EMQX was started.
• Fixed an issue where messages that failed to be delivered due to unregistered topics were not retransmitted when topics were successfully registered with the MQTT-SN client.
• Fix EMQX startup output error log when duplicate plugins are configured in loaded_plugins file.
• Fix MongoDB related features outputting excessive error logs when configured incorrectly.
• Add format check for Dashboard User and AppID, special characters such as / are not allowed.
• Corrected the reason code in the DISCONNECT packet returned when kicking the client to 0x98.
• Auto subscriptions will ignore empty topics.

4.4.1

Release Date: 2022-02-18

NOTE: 4.4.1 is in sync with: 4.3.7. The compare base of this change set is 4.4.0.

Important changes

• A cluster-wide total connections calculation bug was fixed in in Enterprise edition 4.4.1. Previously only the individual node's local number of connections were checked against the max number of connections allowed by the license. After this fix, the total number of connections is aggregated cluster-wide every 5 seconds. An extra 10% overrun is allowed to compensate the delays in aggregation.
• The slow subscription feature is improved. It supports counting the time spent in the process of message transmission, and recording and displaying time-consuming clients and topics. Users planning to upgrade should be aware of the possibility that this change may cause clients to reach the license limit and not be able to connect.
• Rules engine supports Lindorm database
• Support client-level message drop metrics
• Optimize online Trace log display on Dashboard, support syntax highlighting

Minor changes

• Support alarm about the usage rate of license connections. By default, the number of connections reaches 80% of the allowed number of licenses, and the alarm is raised. When it is less than 75%, the alarm is cleared. User can also customize in emqx.conf: license.connection_high_watermark_alarm , license.connection_low_watermark_alarm
• Support alarm about license expiration, when the validity period is less than 30 days, the alarm will be raised
• Rule engine supports the configuration of rules and actions for the event of abnormal loss of client messages to enhance the user's custom processing capabilities in this scenario
• Improve the relevant metrics during the execution of the rule engine SQL matching
• Fuzzy search on client supports special characters such as *, (, )
• Improve ACL-related metrics to solve the issue that the count does not increase due to hitting the ACL cache
• Added connected_at field to webhook event notifications
• Log client state before terminating client due to holding the lock too long

Bug Fixes

• Fix the issue that data import and export were not available in some cases
• The module update mechanism is improved to solve the issue that the module is unavailable after the update fails
• Fix the issue that the rule engine did not perform type checking when executing the size comparison statement
• Fix the issue that the related counts are cleared after updating the rule engine action
• Fixed the issue that the metrics interface does not return authentication metrics such as client.acl.deny by default
• Fixed the issue that the subscription query interface did not return paginated data
• Fix the issue of parsing failure when STOMP handles TCP sticky packets
• Fix the issue where the session creation time option was not available when filtering clients
• Fix the issue where memory alarms might not be triggered after restarting
• Fix the crash of import data when user data exists in emqx_auth_mnesia plugin

4.4.0

Release Date: 2021-12-21

EMQX Enterprise 4.4.0 mainly includes the following changes:

Important changes

• Starting from 4.4, EMQX releases are named with Erlang/OTP release in the package name. e.g. emqx-ee-4.4.0-otp24.1.5-3-centos7-arm64.rpm

• For Debian/Ubuntu users, Debian/Ubuntu package (deb) installed EMQX now now run on systemd. This is to use systemd's supervision functionality to ensure that EMQX service restarts after a crash. The package installation service upgrade from init.d to systemd has been verified, but it is still recommended that you verify and confirm again before deploying to the production environment, at least to ensure that systemd is available in your system

• Rule engine InfluxDB integration adds support for InfluxDB v2 API, rule engine supports InfluxDB 2.0 and InfluxDB Cloud now

• Rule engine adds support for SAP Event Mesh

• Rule engine adds support for MatrixDB

• MongoDB integration supports DNS SRV and TXT Records resolution, which can seamlessly connect with MongoDB Altas

• Supports trace online, users can complete the tracking operation of the client and topic on the Dashboard, and view or download the trace log

• Supports slow subscription statistics, which can be used to find abnormal situations such as message blockage in the production environment in time

• Support dynamic modification of MQTT Keep Alive to adapt to different energy consumption strategies

• Support 4.3 to 4.4 rolling upgrade of clustered nodes. See upgrade document for more dtails.

• TLS for cluster backplane (RPC) connections.

Minor changes

• Dashboard supports viewing the number of active client connections

• Dashboard supports relative paths and custom access paths

• Dashboard remove tab navigation

• Support configuring whether to write integer data to InfluxDB as floating point type

• Supports configuring whether to forward retained messages with empty payload to suit users who are still using MQTT v3.1. The relevant configurable item is retainer.stop_publish_clear_msg

• Multi-language hook extension (ExHook) supports dynamic cancellation of subsequent forwarding of client messages

• Rule engine SQL supports the use of single quotes in FROM clause, for example: SELECT * FROM't/#'

• Optimize the use and interaction of the built-in access control file module

• Change the default value of the max_topic_levels configurable item to 128. Previously, it had no limit (configured to 0), which may be a potential DoS threat

• Improve the error log content when the Proxy Protocol message is received but the proxy_protocol configuration is not turned on

• Add additional message attributes to the message reported by the gateway. Messages from gateways such as CoAP, LwM2M, Stomp, ExProto, etc., when converted to EMQX messages, add fields such as protocol name, protocol version, user name, client IP, etc., which can be used for multi-language hook extension (ExHook)

• HTTP client performance improvement

• Add openssl-1.1 to RPM dependency

Bug Fixes

• Fix the issue that the client process becomes unresponsive due to the blockage of RPC calls between nodes

• Fix the issue that the lock management process ekka_locker crashes after killing the suspended lock owner

• Fix the issue of garbled data when writing data to RocketMQ asynchronously

• Fix the issue of inaccurate statistics of RocketMQ

• Fix the display error of the Dashboard monitoring page when the number of cluster nodes exceeds seven

• Fix the issue that the rule engine may have a higher failure rate when saving data to MySQL

• Fix the issue that the Clickhouse-based offline messaging feature of the rule engine is unavailable

• Fix the issue that the Max Returned Count option in the MongoDB-based offline message feature of the rule engine cannot be used

• Fix the issue that the Path parameter of WebHook action in rule engine cannot use the rule engine variable

• Fix MongoDB authentication module cannot use Replica Set mode and other issues

• Fix the issue of out-of-sequence message forwarding between clusters. The relevant configurable item is rpc.tcp_client_num

• Fix the issue of incorrect calculation of memory usage

• Fix MQTT bridge malfunction when remote host is unreachable (hangs the connection)

• Fix the issue that HTTP headers may be duplicated

4.3.19

Release Date: 2023-03-03

Enhancements

• Add TCP keepalive configuration for Kafka client.

• Improve error messages in the dashboard when adding users to the internal auth database.

• The plugin schema_registry will be enabled by default as an optional feature of rule_engine.

Bug fixes

• Fix the problem that new MQTT TLS connections failed to establish after release hot upgrade. For more detailed information please see: emqx/esockd#170.

• fix the issue that produce messages to RocketMQ cluster using rule-engine failed.

• fix some issues in descriptions of the actions, resources amd emqx-modules.

• fix there's no error logs when query the JWKS server failed.

• Fixed an error when forward MQTT messages with User-Property using the republish action.

• Fix the problem of sending offline messages to clients in reverse order when using Redis offline message feature.

• Fix the problem that the same request sent to different EMQX nodes returns inconsistent results when sending the HTTP API to get the client list in paging mode. Before this change, different lists of clients will be returned if one sends 'GET http://localhost:8081/api/v4/clients?_page=1&_limit=1000' to different EMQX nodes in the cluster.

• When uploading a license, now EMQX will always reload the license, to avoid the case where a user replaces the current license file with new contents.

• Only create EMQX modules locally when the emqx_modules application is started. Before this change, we RPC to all the nodes to create/recreate modules when emqx_modules application get started, so finally we created modules N^2 times on all the nodes (N times on each node).

• Password format for new dashboard users is no longer limited to ^[A-Za-z0-9]+[A-Za-z0-9-_]*$.

• Returning a failure when creating an existing listener in a cluster using the API.

• Delete the files directory when resources/modules/schema_registry were deleted to avoid files leaking.

4.3.18

Release Date: 2022-12-29

Enhancements

• Fix the "ORA-01000: maximum open cursors exceeded" problem when sending data via the emqx oracle resource #1560.

• Add more PSK ciphers support #1619.

• Upgrade Erlang/OTP from 23.3.4.9-3 to 23.3.4.18-1 #1660.

Bug fixes

• Fixed an issue where the configuration would not be reloaded on all nodes in a cluster after importing a backup configuration. #1486

• Fixed an issue where the HTTP API would fail to download a backup configuration file when downloading it from a node where it does not reside in. #1486

• Add validations for the config fields of Kafka resource #1511. Before this change, when creating Kafka resources, some of the config fields had no validity check, such as duration and byte size. Even if arbitrary strings were passed to these fields, the resource could be created successfully, then later leads to runtime error (until resource is updated).

• Avoid delete offline message twice #1522. EMQX while delete offline message in external database when subscriber send a PUBACK or PUBREC packet. But a message with retain = true will be stored twice (in retainer and external database) in case retain message and offline message are used in same time. The reduplicated PUBACK and PUBREC will trigger deleted action twice. And the action-metrics will also increase caused by Rule-SQL execution suceeeed. In most cases this does not generate any exceptions or errors, and only a few databases will report that the message to be deleted does not exist on the second delete. This change will avoid redundant offline message deletion operations.

• Upgrade http client library ehttpc from 0.2.1 to 0.4.2 #1587.

• Added topic validation for emqx_mod_rewrite. The dest topics contains wildcards are not allowed to publish #1589.

• The offline message clickhouse action prints an info level log: Destroyed .. Successfully when enabling a rule #1594.

• Now the rules can be created even though the corresponding resources are not ready #1620. Before this change, one cannot create rules without getting the resources connected. We made it possible in this change, but the newly created rule will be in disabled state.

• Fixed cluster/invite_node crash if node name is not provided #1531.

• Fixed broken error message for bad rpc in /load_rebalance/{node}/evacuation/start #1572.

• Fixed load bootstrap file when no bootstrap user in mqtt_app #1600.

• The expired 'awaiting_rel' queue is not cleared after persistent session MQTT client disconnected #1574. Before this change, if the 'awaiting_rel' queue is full when the MQTT client reconnect to the broker and publish a QoS2 message, the client will get disconnected by the broker with reason code RC_RECEIVE_MAXIMUM_EXCEEDED(0x93), even if the packet IDs in the 'awaiting_rel' queue have already expired.

• Trigger message.dropped hook when QoS2 message is resend by client with a same packet id, or 'awaiting_rel' queue is full #1605.

• After a reconnect, the unacknowledged QoS1/QoS2 messages in non-clean session were not retransmitted periodically as before the reconnect #1617. The configuration zone.<zone-name>.retry_interval specifies the retransmission interval of unacknowledged QoS1/QoS2 messages (defaults to 30s). Prior to this fix, unacknowledged messages buffered in the session are re-sent only once after session take-over, but not retried at configured interval.

• Fix Rule-Engine action Data to InfluxDB exection failed since hot-upgrade from e4.3.0..e4.3.10 to e4.3.11..e4.3.17 #1601.

• Added validation for Kafka action parameters, Segment Bytes should not be greater than Max Bytes #1608.

• Added validation for the duration and bytesize parameters of Pulsar actions #1631.

• Authentication for RocketMQ resource not working #1561. In this change we moved the configuration fields access_key, secret_key and security_token from the data_to_rocket action to the bridge_rocket resource. And we also added a new field namespace for RocketMQ services in Aliyun cloud.

• When dashboard creates a new user, the password length must match 3-32 and the format is ^[A-Za-z0-9]+[A-Za-z0-9-_]*$ #1599.

• When resource creation is too slow, there may be some temporary probing connections left #1641.

• Add the SNI field for SSL connection configuration of Kafka resource #1647.

• Fixed the issue that the MongoDB resource connection process was slow when authentication was enabled #1669.

• Fixed the issue that after the release hot upgrade, EMQX occasionally alarms resources down, and the alarms could not be automatically cleared #1668.

4.3.17

Release Date: 2022-11-26

Enhancements

• Support to use placeholders like ${var} in the Collection field of Rule-Engine's MongoDB actions #1503.

• Add a format check to the host field of the InfluxDB resource in Rule-Engine #1426. The host field should be an ip/domain without scheme and port.

• Make sure listener's tls_versions config value is one or more of tlsv1, tlsv1.1, tlsv1.2, tlsv1.3 #9260.

• Remove useless information from the dashboard listener failure log #9260.

• We now trigger the 'message.acked' hook after the CoAP gateway sends a message to the device and receives the ACK from the device #9264. With this change, the CoAP gateway can be combined with the offline message caching function (in the emqx enterprise), so that CoAP devices are able to read the missed messages from the database when it is online again.

• Support to use placeholders like ${var} in the HTTP Headers of Rule-Engine's Webhook actions #9239.

• Asynchronously refresh the resources and rules during emqx boot-up #9199. This is to avoid slowing down the boot if some resources spend long time establishing the connection.

• Add a warning log if the ACL check failed for subscription #9124. This is to make the ACL deny logging for subscription behave the same as for publish.

• JWT ACL claim supports all action to imply the rules applie to both pub and sub #9044.

• Added a log censor to avoid logging sensitive data #9189. If the data to be logged is a map or key-value list which contains sensitive key words such as password, the value is obfuscated as ******.

• Enhanced log security in ACL modules, sensitive data will be obscured #9242.

• Add management.bootstrap_apps_file configuration to bulk import default app/secret when EMQX initializes the database #9273.

• Added two new configs for deterministic order of authentication and ACL checks #9283. The two new global config names are auth_order and acl_order. When multiple ACL or auth plugins (or modules) are enabled, without this config, the order (in which each backend is queried) is determined by the start/restart order of the plugin (or module). Meaning, if a plugin (or module) is restarted after initial boot, it may get ordered to the end of the list. With this config, you may set the order with a comma-speapated ACL or auth plugin names (or aliases). For example: acl_order = jwt,http, this will make sure jwt is always checked before http, meaning if JWT is not found (or no acl cliam) for a client, then the ACL check will fallback to use the HTTP backend.

• Added configurations to enable more client.disconnected events (and counter bumps) #9267. Prior to this change, the client.disconnected event (and counter bump) is triggered when a client performs a 'normal' disconnect, or is 'kicked' by system admin, but NOT triggered when a stale connection had to be 'discarded' (for clean session) or 'takeovered' (for non-clean session) by new connection. Now it is possible to set configs broker.client_disconnect_discarded and broker.client_disconnect_takeovered to on to enable the event in these scenarios.

• For Rule-Engine resource creation failure, delay before the first retry #9313. Prior to this change, the retry delay was added after the retry failure.

Bug fixes

• Fixed the option to choose the reset_by_subscriber offset reset policy in Kafka Consumer #1463.

• Added the missing tlsv1.3 option to tls_versions in hot-config #1532.

• Made Rule-Engine able to connect SQL server when its listening port is not the default (1433) #1464.

• Make sure Schema-Registry API supports Percent-encoding name in HTTP request URI #1497. Note that the name in POST /api/v4/schemas request body should not be percent-encoded as it's a JSON field value.

• Fix an upgrade issue for JWT authentication plugin #1554. When upgrading from e4.3.9 or earlier, an EMQX internal resource which holds the keys will have to be restarted, during the restart, clients may fail to be authenticated.

• Fix that after uploading a backup file with an non-ASCII filename, HTTP API GET /data/export fails with status code 500 #9224.

• Improve the display of rule's 'Maximum Speed' counter to only reserve 2 decimal places #9185. This is to avoid displaying floats like 0.30000000000000004 on the dashboard.

• Fix the issue that emqx prints too many error logs when connecting to mongodb but auth failed #9184.

• Fix that after receiving publish in idle mode the emqx-sn gateway may panic #9024.

• "Pause due to rate limit" log level demoted from warning to notice #9134.

• Restore old emqx_auth_jwt module API, so the hook callback functions registered in older version will not be invalidated after hot-upgrade #9144.

• Fixed the response status code for the /status endpoint #9210. Before the fix, it always returned 200 even if the EMQX application was not running. Now it returns 503 in that case.

• Fix message delivery related event encoding #9226 For Rule-Engine's input events like $events/message_delivered, and $events/message_dropped, if the message was delivered to a shared-subscription, the encoding (to JSON) of the event will fail. Affected versions: v4.3.21, v4.4.10, e4.3.16 and e4.4.10.

• Make sure Rule-Engine API supports Percent-encoding rule_id and resource_id in HTTP request path #9190. Note that the id in POST /api/v4/rules should be literals (not encoded) when creating a rule or resource. See docs Create Rule Create Resource.

• Calling 'DELETE /alarms/deactivated' now deletes deactived alarms on all nodes, including remote nodes, not just the local node #9280.

• When republishing messages or bridge messages to other brokers, check the validity of the topic and make sure it does not have topic wildcards #9291.

• Disable authorization for api/v4/emqx_prometheus endpoint on management api listener (default 8081) #9294.

4.3.16

Release Date: 2022-10-14

Enhancements

• Added more Kafka action parameter checks

  • TCP send buffer size and max batch size parameters are not allowed to be left blank from the configration UI.
  • The combination of "Produce Strategy" set to 'key_dispatch' and the "Key" set to "none" is now not allowed, the dashboard will get an error with text like: "with strategy set to 'key_dispatch', key is not allowed to be 'none'"

• TLS listener memory usage optimization #9005. New config listener.ssl.$NAME.hibernate_after to hibernate TLS connection process after idling. Hibernation can reduce RAM usage significantly, but may cost more CPU. This configuration is by default disabled. Our preliminary test shows a 50% of RAM usage decline when configured to '5s'.

• TLS listener default buffer size to 4KB #9007. Eliminate uncertainty that the buffer size is set by OS default.

• Disable authorization for api/v4/emqx_prometheus endpoint #8955.

• Added a test to prevent a last will testament message to be published when a client is denied connection #8894.

• More rigorous checking of flapping to improve stability of the system #9045.

• QoS1 and QoS2 messages in session's buffer are re-dispatched to other members in the group when the session terminates #9094. Prior to this enhancement, one would have to set broker.shared_dispatch_ack_enabled to true to prevent sessions from buffering messages, however this acknowledgement costs extra resources.

• Fix delayed publish timing inaccuracy caused by OS time change #8908.

Bug fixes

• Fix load_modules reset after new node joins the cluster. Prior to this fix, if load_modules for a cluster has been changed, adding a new node to the cluster with default modules would cause the other nodes to reset to default too. In this fix, the node which is going to join the cluster will copy the loaded_modules from the oldest node in the cluster.

• Fix getting subscriptions from backends successfully with QoS values out of range [0, 2]. Before this change, when we add subscriptions for clients from backends like Redis or MySQL, we won't validate the QoS. For example if the QoS is an integer -1, the topic was still subscribed successfully with QoS -1, if we send a message to this topic, then an error will occur and the MQTT connection will crash. After this change QoS will be clamped into range [0, 2].

• Fix Rule-Engine increased 'success' counter when get subscriptions from Redis failed (due to query Redis timeout).

• Fix Rule-Engine increased 'success' counter when saving offline messages with QoS = 0. We don't allow saving offline messages to backends with QoS = 0, so we need to increase the 'failed' counter instead of the 'success' counter in this case.

• Fix the verify field is missing from the SSL settings of redis-cluster and redis-sentinel resources.

• Fixed Redis resource liveness problem issue. Prior to this fix, the resource is considered alive when connection can be established. The fix is to perform a PING query to make sure the service is alive.

• Fix the redis-cluster resource prints too many error logs when Redis servers are not avaliable.

• Fixed an internal Redis resource ID clashing. This clashing may cause resources in use getting deleted when deleting another resource.

• Mask secret/password in the resource/module creation UI.

• Fix HTTP client library to handle SSL socket passive signal #9145.

• Hide Redis password in error logs #9071. More changes in Redis client included in this release:

  • Improve Redis connection error logging eredis#19. Also added support for eredis to accept an anonymous function as password instead of passing around plaintext args which may get dumpped to crash logs (hard to predict where). This change also added format_status callback for gen_server states which hold plaintext password so the process termination log and sys:get_status will print '******' instead of the password to console.
  • Avoid pool name clashing [eredis_cluster#22](https://github.com/emqx/eredis_cluster/pull/22. Same format_status callback is added here too for gen_servers which hold password in their state.

• Fix shared subscription message re-dispatches #9094.

  • When discarding QoS 2 inflight messages, there were excessive logs
  • For wildcard deliveries, the re-dispatch used the wrong topic (the publishing topic, but not the subscribing topic), caused messages to be lost when dispatching.

• Fix shared subscription group member unsubscribe issue when 'sticky' strategy is used. Prior to this fix, if a previously picked member unsubscribes from the group (without reconnect) the message is still dispatched to it. This issue only occurs when unsubscribe with the session kept. Fixed in #9119

• Fix shared subscription 'sticky' strategy when there is no local subscriptions at all. Prior to this change, it may take a few rounds to randomly pick group members until a local subscriber is hit (and then start sticking to it). After this fix, it will start sticking to whichever randomly picked member even when it is a subscriber from another node in the cluster. Fixed in #9122

• Fix rule engine fallback actions metrics reset #9125.

4.3.15

Release Date: 2022-09-17

Enhancements

• The exp, nbf and iat claims in JWT authentication support non-integer timestamps

Bug fixes

• Fix rule engine update behaviour which may initialize actions for disabled rules
• Fix inaccurate delayed publish due to OS time changes
• Fix the issue that the IP address bound to the Dashboard listener did not take effect
• Fix the issue that shared subscriptions might get stuck in an infinite loop when shared_dispatch_ack_enabled is set to true
• Fix the issue that the rule engine SQL crashes when subject matching null values

4.3.14

Release Date: 2022-08-29

Enhancements

• Improve the log when LwM2M packet parsing fails
• Improve the rule engine error log, the log will contain the rule ID when the action execution fails
• Improve log when loaded_modules and loaded_plugins files do not exist
• Add a guide for changing the default password on Dashboard
• Improved import performance for Protobuf Schema files

Bug fixes

• Fix client.disconnected event not trigger in some cases
• Fix the issue that the JWK authentication module could not be started later when the JWKS service was not ready in time
• Fix the issue that setting the listener port via an environment variable would prevent either listener from being stopped
• Fix the issue that the built-in database authentication did not distinguish the pagination statistics of the authentication data of the client ID and username
• Fix the issue that the module status would be reset after EMQX restarts after hot upgrade
• Fix Redis driver process leak problem
• Fix rule engine MQTT bridge to AWS IOT connection timeout issue
• Fix GET /listener request crashing when listener is not ready
• Fix the issue that the comparison between any variable and null value in the rule engine SQL always returns false after e4.3.7
• Fix the issue that when the execution priority of ExHook is higher than that of the rule engine, the topic filtered by the ExHook Message Hook will not trigger the rule engine
• Fix the issue that the write request of TDEngine may fail because the peer end closes the network connection
• Fix the issue that the configuration of the MQTT-SN module other than the listener would not take effect
• Fix the issue that the ExHook management process was forcibly killed due to the supervisor shutdown timeout
• Fix the issue that the Client ID parameter in ExProto client.connect hook is not defined
• Fix ExProto not triggering disconnect event when client is kicked

4.3.13

Release Date: 2022-08-11

Important Changes

• Upgraded the OTP version used to solve the low probability of random process unresponsiveness caused by OTP bugs. Users who are still using 4.3 are recommended to upgrade to this version
• From the next release, we will stop supporting macOS 10 and provide an installation package for macOS 11

Enhancements

• Allows the connection process to be configured to be garbage collected after the TLS handshake is complete to reduce memory footprint, which can reduce memory consumption by about 35% per SSL connection, but increases CPU consumption accordingly
• Allows configuring the log level of the TLS handshake log to view the detailed handshake process

Bug fixes

• Fix the issue that EMQX could not be started when deployed through Helm Chart after unmounting the loaded_modules file in ConfigMap

4.3.12

Release Date: 2022-07-29

Enhancement

• Rules engine supports RocketMQ with ACL enabled
• Supports searching and paging of rules in rule engine
• Provides CLI ./bin/emqx check_conf to actively check if the configuration is correct
• Optimize the write performance of TDEngine in the rule engine
• Optimizing Shared Subscription Performance
• Add db_name field to the action of rule engine writing data to TDEngine to improve support for super table

Bug fixes

• Fix the issue that the action count is wrong when the rule engine writes to TDEngine
• Fix the issue that the process pool size setting does not take effect when the rule engine writes to HStreamDB
• Fix the issue that an error was reported when querying the subscription list after the GB/T 32960 plugin was enabled
• Fix the issue that incompatible configuration items when restoring a 4.2 backup to 4.3 with hot configuration enabled
• Fix the issue that once the old version of EMQX is uninstalled after hot upgrade, EMQX will not be able to start again
• Fix the issue that the keep-alive check for UDP clients in the Multilingual Protocol Extension was incorrect, causing clients not to expire
• Fix the issue that the client information in the Multilingual Protocol Extension was not updated in time
• Fix the issue that the license update does not take effect when running after hot upgrade to e4.3.10 and later versions
• Fix the issue that when the client specified Clean Session as false to reconnect, the shared subscription message in the flight window would be re-dispatched to the old session process
• Fix the issue that the new node did not use the cluster license after joining the cluster
• Fix the issue that the emqx_lua_hook plugin cannot cancel the message publishing

4.3.11

Release Date: 2022-06-30

Enhancement

• Rule engine supports persisting data to HStreamDB
• QoS and Retain flag in rule engine's message republish actions can now use placeholders
• Supports exclusive subscriptions, that is, only one subscriber is allowed for a topic
• Dashboard and management API's HTTPS listeners can now use password-protected private key files, providing key_password configuration item
• Support for placeholders %u and %c in topic rewrite rules
• Support setting MQTT 5.0 properties in the API request for message publishing, such as message expiry interval, response topic, etc.
• Optimize the UI when creating rule engine resources, such as folding some uncommon options, etc.
• Opened 4 TCP-related configuration items: KeepAlive, TCP_NODELAY, SO_RCVBUF and SO_SNDBUF for the underlying gRPC connection of ExHook

Bug fixes

• Fix the issue of inaccurate memory calculation in Linux OS, and calculate the memory usage of the current OS instead of the memory usage of EMQX
• Fix the issue that the old disconnect event of ExHook would be triggered later than the new connect event when the client reconnects
• Improve the JWT authentication module's judgment logic for startup status in a cluster environment
• Extend the timeout of DynamoDB resource status query of rule engine to avoid the problem that some overseas resources may not be available
• Fix the issue that the timestamp is not updated when the PostgreSQL data storage plugin persists messages and updates message consumption
• Fix the issue that the rules engine's Tablestore, Lindorm and InfluxDB resources did not check connection status when creating
• Fix rule engine not checking connection status when creating Tablestore, Lindorm and InfluxDB resources
• Fix rule engine not updating metrics correctly when writing to TDEngine resource fails
• Fix the issue that the Cassandra message store plugin persisted retained messages to multiple tables, causing duplicate messages
• Fix the issue that Kafka resources exported from versions prior to 4.3.0 (only when the Produce policy is set to first_key_dispatch) could not be imported into 4.3.0 and later
• Fix the issue that the execution order of topic rewriting and delayed publish is not fixed, now it is fixed to execute topic rewriting first
• Improve the null value handling when rule engine persists data to InfluxDB and Tablestore, now null values will not be written
• Fix the issue that rule engine could not encode MQTT 5.0 user properties
• Fix the issue that the count of connack.auth_error is inaccurate when the client uses a protocol version below MQTT v5.0 to access
• Fix the issue that the UDP listeners of LwM2M and CoAP gateways could not bind to the specified network interface
• Fix Dashboard not starting after removing the default Dashboard user in the configuration file
• Fix client.subscribe hook not being able to reject subscriptions
• If the placeholder in the ACL rule is not replaced, the client's publish or subscribe operation will be rejected
• Fix the issue that TLS was enabled but no TLS connection was actually established with Pulsar

4.3.10

Release Date: 2022-06-01

Enhancement

• Add more time transformation functions to the SQL of rule engine
• Add the float2str/2 function to the SQL of rule engine to support specifying the output precision of floating point numbers
• Rule engine supports connecting to Pulsar using Basic and JWT authentication
• Add service_name option to Oracle resource of rule engine to support Oracle Database RAC
• Support for using JWT for authorization, now MQTT clients can authorize using specific claims that include a pub-sub whitelist
• Improved authentication related metrics to make it easier to understand, now client.authenticate = client.auth.success + client.auth.failure
• Support binding the listener of the REST API to a specified network interface
• Upload license will be automatically synchronized to the entire cluster, no need for each node to upload separately, provide HTTP API
• Support multi-condition query and fuzzy query for user data in authentication and authorization using built-in database as data source
• Supports querying clients using the length of the message queue and the number of dropped messages as conditions
• Support to configure the log time format to be compatible with the time format in older versions
• When use_username_as_clientid is configured to true and the client connects without specifying a username, the connection is now rejected with a reason code 0x85
• Full randomisation of app secrets (previously partially randomised)
• Hot upgrades between incompatible versions will now be rejected
• Allow white spaces in EMQX's installation path
• Boot script fail fast on invalid node name (improve error message readability)

Bug fixes

• Fix the issue that the client could not get the message after going online when using the PostgreSQL offline message plugin
• Fix the issue that the rules engine could not successfully establish a TLS connection with Pulsar in some cases
• Fix the issue that rule engine's SQL function hexstr_to_bin/1 could not handle half-byte
• Fix the issue that the alarm was not cleared when the rule engine resource was deleted
• Fix Dashboard HTTPS listener's verify option not taking effect
• Fix the issue that messages were lost when the peer session was terminated during the delivery of QoS 1 messages through shared subscriptions
• Fix the issue that when the log tracer encounters large packets, the heap size grows too fast and triggers the policy of forcibly closeing the connection process
• Fix the issue that the relevant hooks were not properly uninstalled when the module was disabled, resulting in abnormal functions
• Fix the issue that the MQTT-SN client would be disconnected when retransmitting QoS 2 messages
• Fix the issue that modules that were turned off in the backup file would be automatically enabled after restoring the backup
• Fix the issue that the returned results did not match the query conditions when querying subscriptions with multiple conditions
• Fix rule engine resource connection test not working
• Fix multiple Dashboard display issues

4.3.9

Release Date: 2022-04-18

Enhancement

• Schema registry now supports decoding arbitrary binary payloads to JSON data using gRPC services
• Support for connecting to Pulsar using TLS
• Add mongo_date function for SQL in rule engine, which supports saving timestamps as MongoDB Date objects
• Rule engine supports copying rule for fast reuse
• SQL in rule engine supports zip, gzip and other compression and decompression functions
• Improve the error message when rule engine fails to parse payload
• Improve the connection test for some resources in rule engine
• Support setting execution priority for ExHook
• ExHook callback interface adds a Protobuf field RequestMeta meta to return the EMQX cluster name
• Support local policy for shared subscriptions, which will preferentially send messages to shared subscribers under the node where messages flow in. In some scenarios, the efficiency of shared message scheduling will be improved, especially when the MQTT bridge is configured as a shared subscription
• RSA-PSK-AES256-GCM-SHA384, RSA-PSK-AES256-CBC-SHA384, RSA-PSK-AES128-GCM-SHA256 and RSA-PSK-AES128-CBC- SHA256 four new TLS PSK cipher suites are supported, removing two insecure cipher suites PSK-3DES-EDE-CBC-SHA and PSK-RC4-SHA from the default configuration
• Diagnostic logging for wait_for_table of mnesia
  • Prints check points of mnesia internal stats
  • Prints check points of per table loading stats, help to locate the problem of long table loading time.
• Subscribing to an empty topic is prohibited in strict mode
• Generate default files when loaded_modules and loaded_plugins files do not exist

Bug fixes

• Fix the issue that the TLS configuration item server_name_indication is set to disable and does not take effect
• Fix potential process leak issue in MongoDB driver
• Fix the issue that the password of the default Dashboard user modified via the CLI command would be reset after the node leaves the cluster
• Silence grep and sed warnings in docker-entrypoint.sh
• Fix the backup file cannot be deleted and downloaded when the API path contains ISO8859-1 escape characters
• Fix the issue that the Redis driver would crash when DNS resolution failed, etc
• Fix the issue that the MQTT Bridge plugin cannot be started when only the subscription topic is configured but QoS is not configured
• When creating a rule, if a rule with the same ID already exists, the rules engine will now report an error instead of replacing the existing rule
• Fix the issue that the HTTP driver process pool may not be deleted
• Fix the issue that the module parameters could not be updated again after failing to update
• Fix the incorrect type of some fields in the GB/T 32960 access gateway module in Dashboard
• Fix the issue that the configuration of Bridge resources such as Kafka and Pulsar could not be updated
• Fix the issue that JT/T 808 client authentication fails when anonymous authentication is enabled

4.3.8

Release Date: 2022-04-01

Important changes

• For Docker images, the configuration directory /opt/emqx/etc has been removed from the VOLUME list, making it easier for users to rebuild images with changed configurations.
• CentOS 7 Erlang runtime rebuilt on OpenSSL-1.1.1n (previously 1.0), prior to v4.3.13, EMQX will fail to handshake and trigger malformed_handshake_data exception when clients use certain cipher suites.
• CentOS 8 Erlang runtime system rebuilt on RockyLinux 8. centos8 will remain in the package name for backward compatibility.

Enhancement

• Add Pulsar proxy support for rule engine bridging data to Pulsar.
• Add OOM protection for Kafka producers.
• Add command line interface emqx_ctl pem_cache clean to allow forcibly clear x509 certificate cache to reload immediately after certificate file update.
• Refactored ExProto so that anonymous clients can also be displayed on Dashboard.
• Topic configuration items in bridges can now use ${node} placeholders.
• Add validation of UTF-8 strings in MQTT packets in strict mode. When set to true, invalid UTF-8 strings will cause the client to disconnect.
• MQTT-SN gateway supports initiative to synchronize registered topics after session resumed.
• Improve the writing precision of rule engine floating point data from 10 decimal places to 17 decimal places.
• EMQX will prompt how to modify the initial password of Dashboard at startup.

Bug fixes

• Fix MQTT Subscriber module not being able to use two-way SSL connection.
• Fix the issue that PSKFile module failed to start.
• Fix the issue that Kafka Consumer Group module could not process binary data.
• Fix the issue that Log Trace could not be stopped.
• Fix the issue that the alternate action could not be triggered when the action of the rule engine persisting data to Oracle and Lindorm (only synchronous operation) failed to execute.
• Fix an issue where rule engine data persistence to Oracle failed but the success count still increased.
• Fix the issue that some zone configurations could not be cleared.
• Fix an issue where changes to some monitoring and alarm configurations were invalid after restarting.
• Fix the issue that Schema Registry is not available in the cluster environment.
• Fix the issue that the LwM2M client list query API returned incorrect data in a cluster environment, which resulted in the inability to access the LwM2M gateway module management page.
• Fix the issue that the JT/T 808 location report frame was parsed incorrectly.
• Fix the issue that the el8 installation package cannot be started on Amazon Linux 2022, the error content is errno=13 Permission denied.
• Fix an issue where the client could not reconnect if the connection process was blocked in some cases. Now waiting for more than 15 seconds without a response will force the old connection process to be closed.
• Fix the issue of query resource request timeout when rule engine resource is unavailable.
• Fix the issue of {error, eexist} error when re-run after hot upgrade failed.
• Fix an issue where publishing to a non-existing topic alias would crash the connection.
• Fix 500 error when querying lwm2m client list on another node via HTTP API.
• Fix HTTP API for subscribing topics crashes when invalid QoS are passed in.
• Fix the issue that the connection count was not updated because the related resources were not released when the connection process accessed through the ExProto exited abnormally.
• Fix an issue where the value of server_keepalive configuration item would be incorrectly applied to MQTT v3.1.1 clients.
• Fix Stomp client not firing $event/client_connection event messages.
• Fix the issue that the system memory alarm was incorrectly activated when EMQX was started.
• Fixed an issue where messages that failed to be delivered due to unregistered topics were not retransmitted when topics were successfully registered with the MQTT-SN client.
• Fix EMQX startup output error log when duplicate plugins are configured in loaded_plugins file.
• Fix MongoDB related features outputting excessive error logs when configured incorrectly.
• Add format check for Dashboard User and AppID, special characters such as / are not allowed.
• Corrected the reason code in the DISCONNECT packet returned when kicking the client to 0x98.
• Auto subscriptions will ignore empty topics.

4.3.7

Release Date: 2022-02-11

Important

A cluster-wide total connections calculation bug was fixed in in EMQX Enterprise 4.3.7. Previously only the individual node's local number of connections were checked against the max number of connections allowed by the license. After this fix, the total number of connections is aggregated cluster-wide every 5 seconds. An extra 10% overrun is allowed to compensate the delays in aggregation.

Users planning to upgrade should be aware of the possibility that this change may cause clients to reach the license limit and not be able to connect.

Enhancement

• Support alarm about the usage rate of license connections. By default, the number of connections reaches 80% of the allowed number of licenses, and the alarm is raised. When it is less than 75%, the alarm is cleared. User can also customize in emqx.conf: license.connection_high_watermark_alarm , license.connection_low_watermark_alarm
• Support alarm about license expiration, when the validity period is less than 30 days, the alarm will be raised
• Rule engine supports the configuration of rules and actions for the event of abnormal loss of client messages to enhance the user's custom processing capabilities in this scenario
• Improve the relevant metrics during the execution of the rule engine SQL matching
• Fuzzy search on client supports special characters such as *, (, )
• Improve ACL-related metrics to solve the issue that the count does not increase due to hitting the ACL cache
• Added connected_at field to webhook event notifications
• Log client state before terminating client due to holding the lock too long

Bug fixes

• Fix the issue that data import and export were not available in some cases
• The module update mechanism is improved to solve the issue that the module is unavailable after the update fails
• Fix the issue that the rule engine did not perform type checking when executing the size comparison statement
• Fix the issue that the related counts are cleared after updating the rule engine action
• Fixed the issue that the metrics interface does not return authentication metrics such as client.acl.deny by default
• Fixed the issue that the subscription query interface did not return paginated data
• Fix the issue of parsing failure when STOMP handles TCP sticky packets
• Fix the issue where the session creation time option was not available when filtering clients
• Fix the issue where memory alarms might not be triggered after restarting
• Fix the crash of import data when user data exists in emqx_auth_mnesia plugin

4.3.6

Release Date: 2021-12-17

Enhancement

• Rule engine supports Ali Lindorm database now
• Support the configuration of whether to continue to deliver empty retained messages to suit users who are still using the MQTT v3.1 protocol
• Optimize the use and interaction of the built-in access control file module

Bug fixes

• Fix the issue of incorrect calculation of memory usage
• Fix the issue that the Path option of Webhook Action in rule engine doesn't support the use of ${Variable}
• Fix the issue of garbled data when writing data to RocketMQ asynchronously
• Fix the issue of inaccurate statistics of RocketMQ
• Fix the issue that the connection failure log will continue to be printed when updating or deleting MQTT Bridge and MQTT Subscribe resources in some cases
• Fix the issue that the rule engine may have a higher failure rate when saving data to MySQL
• Fix the issue that the Clickhouse-based offline messaging feature of the rule engine is unavailable
• Fix the issue that the Max Returned Count option in the MongoDB-based offline message feature of the rule engine cannot be used
• Fix the issue of partial hot configuration failure

4.3.5

Release Date: 2021-11-05

Enhancement

• Improve client kick (forced step-down)
• Add support for new cipher suites for LwM2M gateway
• Introduced interleaving for priority queues (to avoid low priority queue stavation)
• HTTP authentication plugin disable superuser requests by default
• Improve InfluxDB write performance
• InfluxDB Tag Name and Field Name support the use of placeholders

Important fixes

• Fix the issue that calls between clusters may cause the client process to lose response
• WebHook's HTTP client SSL configuration parse
• MongoDB resources allow host names
• Performance improvement for built-in database ACL (emqx_auth_mnesia)
• Fix the issue that the authentication based on the built-in database incorrectly transcodes the HTTP request parameters
• Fix the issue that the MySQL authentication module may fail to start
• Fix some issues of STOMP gateway

Minor fixes

• Fix the wrong status of Kafka and MongoDB resources of the rule engine
• Fixed the issue that the Client ID containing "" characters could not be searched in a fuzzy manner
• Fix the issue that variable byte integers may be larger than 4 bytes
• Fix the issue that duplicate modules may be added
• Fix the issue that the Listener cannot be restarted on the Dashboard

4.3.4

Release Date: 2021-09-18

Enhancement

• Rule engine Data bridge to pursar supports data compression
• Extend the timeout interval for creating rules

Bug fixes

• Fix rule engine data saved to InfluxDB performance issues
• Fixes an issue where WebHook inability to configure sni caused HTTPS to not be available in some cases
• Fix an issue where resources cannot be released after the rule is shut down by the rule engine
• Fixes an issue where the rule engine offline messages cannot be deleted after receiving them in some cases

4.3.3

Release Date: 2021-08-16

Enhancement

• Save offline messages to Redis to support clearing residual data
• ExHook to add automatic reconnection mechanism, timeout parameters and alternative actions

Bug fixes

• Fix the rule engine can't connect to InfluxDB using HTTPS
• Fix the rule engine data saving to InfluxDB action cannot use placeholder
• Fix the rule engine data bridging to WebServer can not use Path
• Repair grpc-client timeout processing logic.
• Fix ExProto bug, add retry logic, reduce some unnecessary printing

4.3.2

Release Date: 2021-07-17

Enhancement

• The client adds more fields to the on/offline message

Bug fixes

• Fix an issue where the LwM2M Gateway Management page could not be opened
• Fix an issue where custom fields cannot be resolved in a resolution location escalation for the JT/T808 gateway
• Fix an acl.conf file format error that invalidated the ACL rule
• Fix an issue where creating a auth_ldap authentication module failed
• Fix an issue that cannot be stopped in the case of a multilingual protocol resolution exception
• Fix an issue where the Rule Engine was unable to create Oracle resources
• Fix an issue where the Rule Engine failed to synchronize bulk writes to SQL Server

4.3.1

Release Date: 2021-06-05

Enhancement

• New Rule Engine Description of the TimeRange field in Offline Message Save

Bug fixes

• Rule engine Problems where data cannot be written in the case of An OpenTSDB exception
• An issue with the wrong display in the hotly upgraded version
• MQTT-SN protocol 'cleansession'false' client loses the topicid when recovering the session
• There is a problem with the preset module modifying the configuration after the restart
• Dashboard rule engine editing shows an error issue
• Dashboard navigation breadcrumbs show problems

4.3.0

Release Date: 2021-05-19

Enhancement

• Rule engine supports Kafka to add partitions
• Rule engine supports offline message and auto-subscription using ClickHouse Storage
• The batch and async mode is enabled by default for the actions of the rule engine, if the actions support batch and asnyc
• Refactoring and improving the performance of data-to-InfluxDB
• Using Kafka to send MQTTmessage to support the set payload format

Bug fixes

• The rule engine will make mistakes when editing actions
• Fix i18n translate of module in Dashboard
• The rule engine supports writing null to the database

4.2.13

Release Date: 2022-08-10

Enhancement

• Hot upgrades between incompatible versions will now be rejected
• Support binding the listener of the HTTP API to a specified network interface
• Boot script fail fast on invalid node name, improve error message readability

Bug fixes

• Fix the issue that hot configuration items did not take effect after restoring from backup
• Fix the issue that the rule engine data is not replicated to disk in the cluster, resulting in the problem that the rule engine data will be lost after restarting the cluster after the only node that writes data to disk leaves the cluster
• Fix the issue that the rule engine would get a 500 error when performing a connection test on an unavailable resource
• Fix connection test always passing when creating MongoDB resource in rules engine
• Fix rule engine not updating metrics correctly when writing to TDEngine resource fails
• Extend the timeout of DynamoDB resource status query of rule engine to avoid the problem that some overseas resources may not be available
• If the placeholder in the ACL rule is not replaced, the client's publish or subscribe operation will be rejected
• Fix the issue that the execution order of topic rewriting and delayed publish is not fixed, now it is fixed to execute topic rewriting first
• Fix the issue that modules that were turned off in the backup file would be automatically enabled after restoring the backup
• Fix the issue that the MQTT-SN client would be disconnected when retransmitting QoS 2 messages
• Fix Dashboard HTTPS listener's verify option not taking effect
• Fix multiple Dashboard display issues

4.2.12

Release Date: 2022-07-11

Bug fixes

• Fix the issue that the hot configuration function cannot continue to be used after hot upgrade

4.2.11

Release Date: 2022-04-26

Important changes

• A cluster-wide total connections calculation bug was fixed in in Enterprise edition 4.2.11. Previously only the individual node's local number of connections were checked against the max number of connections allowed by the license. After this fix, the total number of connections is aggregated cluster-wide every 5 seconds. An extra 10% overrun is allowed to compensate the delays in aggregation. Users planning to upgrade should be aware of the possibility that this change may cause clients to reach the license limit and not be able to connect.

Note: The WebSocket listener will be restarted when e4.2.0 and e4.2.1 are hot-upgraded to a higher version, so WebSocket connections will be disconnected for a short time, please pay attention when upgrading.

Enhancement

• MQTT-SN gateway supports initiative to synchronize registered topics after session resumed.
• Improve the relevant metrics during the execution of the rule engine SQL matching
• Improve the error message when rule engine fails to parse payload

Bug fixes

Rule Engine

• Fix the issue that rule engine data persistence to Oracle failed but the success count still increased
• Fix the issue that the alternate action could not be triggered when the action of the rule engine persisting data to Oracle (only synchronous operation) failed to execute
• Fix the issue that enabling system messages would cause rule engine's Kakfa action to crash
• Fix the issue of query resource request timeout when rule engine resource is unavailable
• If a rule with the same ID already exists when creating a rule, , rule engine will now report an error instead of replacing the existing rule

Protocol

• Fix the issue that the configuration item server_keepalive would be incorrectly applied to MQTT v3.1.1 clients
• Fix the issue that the JT/T 808 location report frame was parsed incorrectly
• Fix the issue that messages that failed to be delivered due to unregistered topics were not retransmitted when topics were successfully registered with the MQTT-SN client

REST API & CLI

• Fix the issue that incorrect query results were returned when querying subscriptions using multiple condition
• Fix the issue that the subscription query interface did not return paginated data
• Add the format check for Dashboard User and AppID to avoid User and AppID containing some special characters cannot be deleted
• Fix the issue that the metrics interface does not return authentication metrics such as client.acl.deny by default
• Fix the issue that the LwM2M client list query API returned incorrect data in a cluster environment, which resulted in the inability to access the LwM2M gateway module management page

Dashboard

• Fix the issue that the session creation time option was not available when filtering clients
• Fix multiple UI display issues

Other

• Fix various issues of hot config, such as the configuration cannot be cleared, the updated configuration is invalid after restarting, etc
• Fix the issue that the MQTT Bridge plugin cannot be started when only the subscription topic is configured but QoS is not configured
• Fix an issue with plugin default startup list, now duplicate plugin startup items in loaded_plugins file will be ignored
• Fix the issue that auto subscriptions might subscribe to an empty topic
• Fix the issue that Message ID displayed garbled characters in some logs

4.2.10

Release date: 2022-01-13

Enhancement

• The action's metrics in rule engine will no longer be cleared when updating
• Supports configuring whether to forward retained messages with empty payload to suit users who are still using MQTT v3.1. The relevant configurable item is retainer.stop_publish_clear_msg
• Optimize the use and interaction of the built-in access control file module
• Change the default value of the max_topic_levels configurable item to 128. Previously, it had no limit (configured to 0), which may be a potential DoS threat
• Improve the error log content when the Proxy Protocol message is received but the proxy_protocol configuration is not turned on

Important fixes

• Fix the issue that the rule engine may have a higher failure rate when saving data to MySQL
• Fix the issue of garbled data when writing data to RocketMQ asynchronously
• Fix the issue of inaccurate metrics of RocketMQ
• Fix the issue that the Max Returned Count option in the MongoDB-based offline message feature of the rule engine cannot be used
• Fixed an issue that health checks on resources could block the creation process

Minor fixes

• Fixed the issue that the Retain Handling subscription option in the proxy subscription module could not be configured to 2
• Fix the issue that the client list obtained by filtering by session creation time is inaccurate
• Fix Erlang VM memory calculation error in Dashboard node details page
• Removed run-time configurable items that have expired, support more run-time configurable items

4.2.9

Release date: 2021-11-17

Enhancement

• Improve client kick (forced step-down)

Important fixes

• Fix the issue that calls between clusters may cause the client process to lose response
• Fix the issue that modules reporting errors after multiple startups and shutdowns
• Fix the issue that lock release may cause the client process to crash in some cases

Minor fixes

• MongoDB resources allow host names
• Fix some issues of MongoDB authentication module
• Fixed the issue that the Client ID containing "\" characters could not be searched in a fuzzy manner
• Fix the issue that variable byte integers may be larger than 4 bytes
• Fix the issue that the same module may be added repeatedly
• Fixed the issue that the new configuration actually took effect after modifying the Action-related configuration in Dashboard, but the Dashboard did not refresh the display

4.2.8

Release date: 2021-09-29

• Fix an issue that the rule engine failed to synchronize batch write to SQL Server
• Fix an issue that the rule engine cannot create Oracle resources
• Fix an issue that multi-language protocol analysis cannot be stopped under abnormal conditions
• Fix an issue of failure to create LDAP Auth authentication module
• Fix an issue where custom fields could not be parsed in the JT/T808 gateway parsing location report
• Fix an issue that rule engine offline messages cannot be deleted after being received in some cases
• Fix an issue that resources cannot be released after the rule engine is closed
• Enhanced saving of offline messages to Redis to support clearing residual data
• Fix an issue that the error code returned by the backend is not clear when the wrong data format is entered when searching on the client
• Fix an issue that the client's protocol name is incorrectly displayed after the MQTT-SN client is connected
• Fix an issue that the client process may be stuck, causing some clients to fail to connect
• Fix an issue that the client cannot access after proxy-protocol is turned on.
• Fix an issue where the client page displayed incorrect Socket type after proxy-protocol was turned on
• Fix an issue of "Connection process is not alive" when calling exproto's ConnectionAdapter method across nodes in the cluster
• Fix a bug that caused a zombie on the Kafka client due to network fluctuations
• Webhook supports switching http-pipelining , which is disabled by default
• Added support for ipaddrs in acl.conf
• Optimize an issue of printing a large number of useless logs when the exproto client is disconnected

4.2.7

Release date: 2021-06-17

• Fix an issue where rule engine data is saved to an openTSDB exception that cannot be written
• Fix A hot configuration issue cannot be performed on dashboard in a special case
• Fix the problem that the client of the MQTT-SN protocol cleansession-false lost topicid when restoring the session
• Fix MQTT-SN the client is stuck in an abnormal situation
• Fix an issue where rule engine data is forwarded to a WebServer SSL configuration that does not take effect
• Fix an issue where module Kafka consumer group SSL configurations do not work
• Fix rule engine The problem with editing a resource that prevents the list of resources from appearing
• Enhanced exception handling of failed import lice

4.2.6

Release date: 2021-04-28

• Fix the problem that the module cannot be started after stopping under special circumstances
• Fix the problem of the time format of the alarm list
• Fix the problem that the MQTT-SN client goes offline abnormally and the Will message is not sent
• Fix the problem that PUBLISH and REGACK are out of order when the MQTT-SN client reconnects and cleansession=false
• Fix the problem of partial display errors in Dashboard
• Update Log default output in File

4.2.5

Release date: 2021-03-10

• Fix an issue with the Pulsar consumer group resolving bulk message errors
• Fix an issue that cannot be resolved in the event of an MQTT protocol exception
• Fix an issue where an error was displayed in the exception of the Dashboard subscription list
• Fix a bulk message performance issue that the rule engine handles for a single process

4.2.4

Release date: 2021-02-18

• New rule engine update resource logic
• Added new rule engine, data bridge to kafka supports configuration of cache size
• Fix the situation where the AUTH_HTTP long connection is disconnected when the Keepalive timeout period or the maximum number of requests is reached, causing the request to be lost
• Fix the issue of WebHook SSL certificate configuration
• Fix the problem of AuthRedis reconnection failure
• Fix the issue of checking MQTT Topic format when creating Kafka consumer group
• Optimize the theme statistics page moved to the module management page

4.2.3

Release date: 2020-12-25

• New GT/T32960 protocol access
• New Rule Engine SQL statements support binary data operation functions
• Adjust the rule engine/module interface parameters uniformly
• Optimize the LWM2M access process
• Optimize webHook plug-in performance
• Fix The rule engine redis sentinel mode failed to create a resource

4.2.2

Release date: 2020-12-10

• Optimize AuthHttp performance issues
• Add new rule engine data save to Oracle
• Added rule engine data save to DolphinDB
• Added rule engine data saving to MS SQL server
• Enhanced rule engine data saving support synchronous and asynchronous
• Fix the problem of inaccurate counting in the asynchronous mode of the rule engine
• Added SSL support to configure the depth of the CA certificate
• Fix the abnormal problem in the hot upgrade

4.2.1

Release date: 2020-11-16

• Added Dashboard module page to support management mqtt enhanced authentication
• Added Dashboard module page to support management of lwm2m client
• Added redis resources to support configuring SSL parameters
• Added auth_jwt to support JWKs
• Added alert message when subscriber TCP is busy
• New rule engine, data bridge to kafka, support ACK policy configuration
• Optimize Dashboard monitoring page
• Optimize emqx_exporto performance
• Optimize emqx_exhook performance
• Fix the wrong action type when editing actions in dashboard
• Fix rule engine-resource typo
• Fix the failure of import and export recovery in cluster
• Fix the problem that the rule engine MySQL resource cannot use the domain name
• Fix the problem that the message is too large when the data is bridged to Kafka

4.2.0

Release date: 2020-10-13

• Rule engine Mysql/MongoDB/Cassandra/PGsql resource supports IPV6 and SSL connection
• The rule engine "resources" supports uploading certificates
• Rule engine "action" group
• Fix InfluxDB not supporting underscore characters
• Support dynamic creation and configuration of functional modules
• Support more parameter hot configuration
• Support hot upgrade between minor version numbers
• Remove emqx_auth_username and emqx_auth_clientid plugins
• Refactor emqx_auth_mnesia, compatible with the data import of the old version emqx_auth_username and emqx_auth_clientid
• The emqx main configuration file is split and supports include configuration files

4.1.5

Release Date: 2020-08-30

EMQX 4.1.5 is released now, it fixes a bug in MQTT message parser.

4.1.4

Release Date: 2020-08-29

EMQX 4.1.4 is released now, it mainly includes the following changes:

emqx

Bug fixes:

• Fix the issue of abnormal memory growth caused by the topic metrics feature

  Github PR: emqx#3680

emqx-bridge-mqtt

Enhancements:

• The clientid configuration item supports ${node} placeholders to optimize the user experience under the cluster

  Github PR: emqx-bridge-mqtt#99

emqx-management

Bug fixes:

• Fix the issue that the data migration function is not available under Windows

  Github PR: emqx-management#262

emqx-lua-hook

Bug fixes:

• Fix the issue that the Username field cannot be obtained

  Github PR: emqx-lua-hook#115

4.1.3

Release Date: 2020-07-24

EMQX 4.1.3 is released now, it mainly includes the following changes:

emqx-management

Bug fixes:

• Add type checking for the payload field in PUBLISH API

  Github PR: emqx/emqx-management#250

emqx-retainer

Bug fixes:

• Fix the issue that the retained message will not be sent when the subscription topic contains both '+' and '#'

  Github PR: emqx/emqx-retainer#146

4.1.2

Release Date: 2020-08-08

• Fixes some known issues

4.1.1

Release Date: 2020-08-07

1. rule_engine adds Pulsar consumer group resources
2. rule_engine add Kafka consumer group resources
3. rule_engine Add data and save to TDengine database
4. rule_engine Add offline message save to MySQL action
5. rule_engine Add offline message save to PostgreSQL action
6. rule_engine Add offline message and save to Cassandra action
7. rule_engine Add offline message and save to MongoDB action
8. rule_engine Add to get subscription relationship from MySQL
9. rule_engine Add to get subscription relationship from PostgreSQL
10. rule_engine Add to get subscription relationship from Cassandra
11. rule_engine Add to get subscription relationship from MongoDB
12. rule_engine Save data to MongoDB Action support message template
13. Fix the bug that the HTTP Publish API cannot support the json format of the payload

4.1.0

Release Date: 2020-07-18

1. Built-in preview version license, you can start emqx directly without registering on the official website to get the license
2. Modify the license expiration policy, the emqx service will not stop, but the new connection cannot log in
3. Rule engine add MQTT subscription resources
4. Rule engine MQTT message bridge support pool
5. Rule engine MQTT message bridge fixes the cluster cannot use the bug
6. Rule engine Add data and save to ClickHouse database
7. InfluxDB supports http/https connection
8. Enterprise edition multi-language development supports northbound message processing
9. Rule engine Add offline message and save to redis action
10. Rule engine add to get subscription relationship from redis

4.0.5

Release date: 2020-03-17

EMQX 4.0.5 is now released, which mainly fixed some bugs.

EMQX

Bugs fixed:

• Fix GC strategy

  Github PR: emqx/emqx#3317

• Fixed the issue where the value of the Maximum-QoS attribute was set incorrectly

  Github issue: emqx/emqx#3304, emqx/emqx#3315 Github PR: emqx/emqx#3321

• Fixed the issue where the CPU usage rate increased abnormally every 15 seconds when EMQX was running in a Docker environment

Github issue: emqx/emqx#3274 Github PR: emqx/emqx-rel#462

• Fix the issue that the node.* configuration item in the configuration file does not take effect

  Github issue: emqx/emqx#3302 Github PR: emqx/emqx-rel#463

emqx-rule-engine (plugin)

Bugs fixed:

• Fix the issue that the rule engine does not support Payload as UTF-8 string

  Github issue: emqx/emqx#3287 Github PR: emqx/emqx#3299

emqx-sn (plugin)

Bugs fixed:

• Fix the issue of missing MQTT-SN subscription

  Github issue: emqx/emqx#3275 Github PR: emqx/emqx-sn#156

4.0.4

Release Date: 2019-03-06

EMQX 4.0.4 is now released, which mainly fixed some bugs.

emqx

Bugs fixed:

• Fix the issue that the acl_deny_action configuration item does not take effect

  Github issue: emqx/emqx#3266

  Github PR: emqx/emqx#3286

• Fix wrong type of mountpoint configuration item

  Github issue: emqx/emqx#3271

  Github PR: emqx/emqx#3272

• Fix the issue that the peer_cert_as_username configuration item does not take effect

  Github issue: emqx/emqx#3281

  Github PR: emqx/emqx#3291

• Fix the problem that the error log is still printed even if the connection is closed normally

  Github PR: emqx/emqx#3290

emqx-dashboard (plugin)

Bugs fixed:

• Fix the problem that the Dashboard node displays a blank in the drop-down list

  Github issue: emqx/emqx#3278

  Github PR: emqx/emqx-dashboard#206

• emqx-retainer (plugin)

  Bugs fixed:

  • Corrected the behavior when the retained message limit is reached, allowing replacement of existing retained messages instead of preventing storage of any new retained messages.

    Github PR: emqx/emqx-retainer#136

4.0.3

Release Date: 2019-02-21

EMQX 4.0.3 has been released. This version primarily includes bug fixes.

emqx

Enhancements:

• Added an option to allow clients to bypass the authentication plugin when logging in.

  Github PR: emqx/emqx#3253

Bugs fixed:

• Fixed an issue where unnecessary error logs were printed under certain race conditions.

  Github PR: emqx/emqx#3246

emqx-management (plugin)

Bugs fixed:

• Removed unused fields and functions, and fixed issues with abnormal field values.

  Github PR: emqx/emqx-management#176

• Fixed an issue where the client list could not be retrieved in a cluster environment.

  Github PR: emqx/emqx-management#173

• Fixed issues with HTTPS listener options.

  Github PR: emqx/emqx-management#172

• Corrected the return format of the application list.

  Github PR: emqx/emqx-management#169

4.0.2

Release Date: 2019-02-07

EMQX 4.0.2 has been released. This version focuses on bug fixes and performance optimizations.

emqx

Enhancements:

• Improved JSON encoding and decoding performance.

  Github PRs: emqx/emqx#3213, emqx/emqx#3230, emqx/emqx#3235

• Reduced the size of generated projects.

  Github PR: emqx/emqx#3214

Bugs fixed:

• Fixed an issue where DISCONNECT packets were not sent in certain situations.

  Github PR: emqx/emqx#3208

• Fixed an issue where receiving PUBLISH packets with the same PacketID would cause a disconnection.

  Github PR: emqx/emqx#3233

emqx-stomp (plugin)

Bugs fixed:

• Fixed an issue where the max connection limit was not enforced.

  Github PR: emqx/emqx-stomp#93

emqx-auth-redis (plugin)

Bugs fixed:

• Fixed an issue where internal modules failed to start.

  Github PR: emqx/emqx-auth-redis#151

cowboy (dependency)

Bugs fixed:

• Fixed an issue where WebSocket connections did not send will messages in certain situations.

  Github Commit: emqx/cowboy#3b6bda

4.0.1

Release Date: 2019-01-17

EMQX 4.0.1 has been released. This version focuses on bug fixes and performance optimizations.

emqx

Enhancements:

• force_shutdown_policy is disabled by default.

  Github PR: emqx/emqx#3184

• Added support for scheduled global garbage collection (GC) with configuration options.

  Github PR: emqx/emqx#3190

• Optimized default configuration for force_gc_policy.

  Github PRs: emqx/emqx#3192, emqx/emqx#3201

• Optimized Erlang VM parameter configurations.

  Github PRs: emqx/emqx#3195, emqx/emqx#3197

Bugs fixed:

• Fixed an issue where using incorrect units caused the blacklist feature to malfunction.

  Github PR: emqx/emqx#3188

• Fixed handling of the Retain As Publish flag and ensured the Retain flag value is preserved in bridge mode.

  Github PR: emqx/emqx#3189

• Fixed an issue where multiple WebSocket listening ports could not be used.

  Github PR: emqx/emqx#3196

• Fixed an issue where EMQX might not send DISCONNECT packets during session takeover.

  Github PR: emqx/emqx#3208

emqx-rule-engine

Enhancements:

• Added more SQL functions to operate on arrays.

  Github PR: emqx/emqx-rule-engine#136

• Reduced performance impact when no rules are configured.

  Github PR: emqx/emqx-rule-engine#138

emqx-web-hook

Bugs fixed:

• Fixed a crash issue caused by parameter mismatches.

  Github PR: emqx/emqx-web-hook#167

4.0.0

Release Date: 2019-01-10

The official release of EMQX 4.0.0 is now available. In this version, we significantly improved throughput performance by refactoring the channel and session, enhanced extensibility by adding more hooks and metrics, redesigned the SQL for the rule engine, and optimized the performance of the Edge version.

General

Enhancements:

• Architecture optimization to greatly improve message throughput and reduce CPU and memory usage.
• Improved MQTT 5.0 message handling process.
• Introduced new SQL statements for the rule engine.
• Renamed metrics and added additional metrics.
• Updated hook parameters and added more hooks.
• Added publish and subscribe command-line interfaces for emqtt.

Bugs fixed:

• Fixed an issue where SSL handshake failures caused crashes.
• Fixed an issue where the max_subscriptions configuration was not effective.
• Fixed an issue with out-of-order message forwarding in cross-cluster communication.
• Fixed an issue where the CLI could not retrieve multiple routes for a single topic.

REST API

Enhancements:

• Added support for IPv6.
• Changed the default REST API listening port from 8080 to 8081 to avoid conflicts with other applications.
• Removed all session-related endpoints.
• Renamed "connections" to "clients" and incorporated previous session functionalities.
• Added support for returning the actual topic of shared subscriptions in the subscription query API.
• Added support for configuring default AppID and AppSecret.
• The REST API for publishing messages now supports payloads encoded in base64.

Bugs fixed:

• Fixed an issue where encoded URIs were not handled correctly.

Authentication

Enhancements:

• The HTTP authentication plugin now supports user-defined HTTP request headers.
• The clientid and username authentication plugins once again support configuring default clientid and username via the configuration file.