The PR bumps aiomqtt from <=0.1.3 to <=2.4.0, but aiomqtt v2.x introduced a completely redesigned async-first API that is incompatible with the existing usage in examples/mqtt.py. The example still uses the old paho-mqtt-style callback API (on_connect, on_disconnect, on_message, loop_forever, client.connect, client.reconnect) which no longer exists in aiomqtt 2.x. Allowing the new version without updating the example will result in runtime errors for anyone using that example. The constraint should either be kept at <=0.1.3 until the example is updated, or the example must be rewritten to use the async context manager / message iterator pattern introduced in aiomqtt 1.x+.

examples/mqtt.py (line 86): This line uses the old aiomqtt 0.x constructor signature (aiomqtt.Client(loop, userdata=userdata, transport=transport)). In aiomqtt 2.x the client is used as an async context manager (async with aiomqtt.Client(hostname, ...) as client:) and the loop and userdata parameters no longer exist. This will raise a TypeError at runtime with the newly allowed version.

examples/mqtt.py (line 87): The callback-based API (client.on_connect, client.on_disconnect, client.on_message) was removed in aiomqtt 1.x. Messages are now consumed via async for message in client.messages:. These three lines will silently do nothing or raise AttributeError.

examples/mqtt.py (line 96): client.loop_forever() does not exist in aiomqtt 2.x. The event loop integration is handled internally by the async context manager.

examples/mqtt.py (line 98): await client.connect(host, port, keepalive) was removed; connection is established by entering the async context manager (async with aiomqtt.Client(hostname=host, port=port, keepalive=keepalive) as client:).

examples/mqtt.py (line 102): await client.reconnect() no longer exists in aiomqtt 2.x. Reconnection logic must be implemented by re-entering the context manager, typically in a retry loop.

pyproject.toml (line 69): The jump from <=0.1.3 to <=2.4.0 crosses two major version boundaries with breaking API changes. If the intent is to keep backward compatibility while allowing a patch/minor bump, the constraint should be tightened (e.g. >=2.0,<=2.4.0) once the example is updated. As written, it also still allows the old 0.1.3 version due to the <= bound starting from whatever was previously installed.

This PR updates the aiomqtt version constraint from <=0.1.3 to <=2.4.0, which is a major version jump spanning two breaking API rewrites. The aiomqtt library underwent a complete redesign between v0.x and v2.x: it moved from a paho-mqtt callback-based wrapper to a fully async context manager API. The existing examples/mqtt.py uses the old v0.x API (passing loop and userdata to the constructor, assigning on_connect/on_disconnect/on_message callbacks, calling client.connect(), client.loop_forever(), and client.reconnect() directly), all of which are absent in v2.x. Allowing <=2.4.0 means pip will resolve to v2.4.0 by default, breaking the example entirely. The example should be updated to the new async API, or the constraint should target a specific compatible range.

examples/mqtt.py (line 86): This file uses the aiomqtt v0.x API, which is completely incompatible with v2.x. aiomqtt.Client no longer accepts a loop or userdata argument — the constructor now only takes connection parameters (hostname, port, etc.). The callback-based pattern (client.on_connect, client.on_message, etc.) was removed; the v2.x API uses async with aiomqtt.Client(...) as client: and async for message in client.messages: instead. Methods like client.connect(), client.loop_forever(), and client.reconnect() no longer exist as standalone calls. This example will fail at runtime with any version of aiomqtt >= 1.0.

pyproject.toml (line 69): Changing the upper bound from <=0.1.3 to <=2.4.0 effectively causes pip to install v2.4.0 by default, which has a completely different public API. If the intent is to support the new API, examples/mqtt.py must be rewritten to match. If the intent is only to keep the dependency up-to-date without breaking changes, consider pinning to the v0.x line with >=0.1.3,<1.0 or rewriting the example alongside the version bump.