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upload-formats-lte-mqtt-protocol

The maximum supported MQTT downlink payload size is approximately 4096 bytes (4 KiB). This includes the complete MQTT message payload (e.g. JSON configuration objects). Messages exceeding this size may result in configuration rejection.

Note: The effective usable payload size may be slightly lower due to protocol overhead.

Practical Implication​

Large configuration objects (e.g. long device whitelists) must remain below this limit. Example: A comma-separated list of ~440 device IDs typically reaches the upper boundary.