The logging configuration of the Check_MK Microcore has been reworked to be configured in a single setting. The log levels have been unified for all these log domains.
Thes configuration options have been deprecated:
The attribute log_level has been removed from cmc_log_cmk_helpers which is now only used to toggle the debug mode of the Check_MK helpers.
The new option is cmc_log_levels (Logging of the core).
The incompatibility is that, if you have configured custom log leves with the options mentioned above before, they are not effective anymore. You will have to set the log levels again using the new option.
In most cases it should be no problem that the log levels are reset, because they are mostly only used for a short time during debugging actions.