Exception in thread "Keep-Alive-Timer" java.lang.OutOfMemoryError: Java heap space log4j:WARN No such property [maxBackupIndex] in org.apache.log4j.DailyRollingFileAppender.

We have noticed since upgrading to major version 6 from 5 a new issue. Every couple of days or so Graylog first starts logging the following: As time goes by more and more of these logs appear and ...