# Hot Update Settings

In EMQX Edge, several of the MQTT broker’s configuration parameters support hot updates. It means you can change them on the fly without restarting the broker.

## Hot Update Configurations

Here are the configurable settings you can update live:

![img](./assets/dashboard-settings-hot-update.png)

- **Property size**: The maximum size (in bytes) of a MQTT user-defined property. These are optional metadata items included in MQTT packets to carry extra information.
- **Max packet size**: The maximum allowed size (in bytes) for MQTT payload that EMQX Edge can accept or send.
- **Client max packet size**: Similar to “Max packet size”, this would define the default maximum packet size a client is allowed to issue.
- **Max mqueue length**: The maximum length of in-flight window queue. It's the maximum number of messages waiting for acknowledgment for QoS 1 or QoS 2.
- **Retry interval**: The interval between retries for QoS 1 and QoS 2 message delivery attempts. Measured in seconds, this also controls the interval of timer in each pipe.
- **Keepalive multiplier**: A multiplier applied to the MQTT Keepalive value. If no activity occurs within the `keepalive * multiplier`, the broker may automatically disconnect idle clients to free resources.
- **Allow anonymous**: Enables or disables connections from clients without authentication.