I just updated to 2022.8.1 (from a 2022.6 release). I got the following in the log:
Logger: homeassistant.components.mqtt
Source: components/mqtt/__init__.py:309
Integration: MQTT (documentation, issues)
First occurred: 12:21:32 (1 occurrences)
Last logged: 12:21:32
The following unsupported configuration options were removed from the MQTT config entry: {'protocol'}. Add them to configuration.yaml if they are needed
Is this anything to be concerned about? I have only ever configured the MQTT integration via the GUI.