I upgraded from 4.0.3 to latest 4.2.3 and in the Error.log is starting to be filled with:
2018.04.19 10:25:29 org.jivesoftware.openfire.container.PluginMonitor - An unexpected exception occurred:
java.util.concurrent.ExecutionException: java.lang.NullPointerException: Plugin could not be located: hazelcast
every half minute or so. I don’t have hazelcast plugin installed and also clustering is disabled. Is there any way to get rid of this error?