: > I'm trying to upgrade Solr from version 4.2 to 4.9, since then I'm ... : haven't configured it. You can ignore this message. To get it to go
The fact that a WARN is logged at all was a bug in 4.9 that got fixed in 4.10... https://issues.apache.org/jira/browse/SOLR-6179 -Hoss http://www.lucidworks.com/