Hi, I’m a maintainer on the open source Egeria project https://github.com/odpi/egeria. We typically use slf4j in our Java 11 code, and depend on slf4j-api. Then in any ‘applications’ (a client tool, or a server) we include an implementation for logging, such as logback – specifically logback-classic We regularly update our dependencies and today I tried upgrading from logback 1.2.11 to 1.4.0. On doing so I see we now fail to startup, as slf4j is unable to find a logging implementation. Slf4j is at 2.0.0. We get an exception Caused by: java.lang.NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder Whilst this is an slf4j config issue in most regards, I wonder if the new logback version is not keeping slf4j happy with its implementation in some way I opened up an issue in our own bug tracker at https://github.com/odpi/egeria/issues/6884 which has the dependency tree & stack trace in full. Is there a change in the new version that’s caught us out? Any indications from the log? (If it is a logback issue happy to open up a bug report, but now knowing logback well figured I’d ask here first!) Many thanks Nigel Jones Unless otherwise stated above: IBM United Kingdom Limited Registered in England and Wales with number 741598 Registered office: PO Box 41, North Harbour, Portsmouth, Hants. PO6 3AU