Jmx configurator classes has been removed in commit fa3de69304h (LOGBACK-1655) thus when logback is starting, the following warn message is displayed:

17:38:25,712 |-WARN in ch.qos.logback.core.model.processor.ImplicitModelHandler - Ignoring unkown property [jmxConfigurator] in [ch.qos.logback.classic.LoggerContext]

This behaviour change is not described in changelog at https://logback.qos.ch/news.html