I'm getting this exception from time to time after updating Rails to 4.2.5.1 and updating a user document
Elasticsearch::Transport::Transport::Errors::Conflict: [409] {"error":"VersionConflictEngineException[[users][0] [user][1]: version conflict, current [7], provided [6]]","status":409}
However I'm not passing any explicit version in the update request. I suppose that two different processes are trying to update the same document at the same time, but it did not change anything apart from Rails version.
I'm using elasticsearch-model (0.1.8) elasticsearch-rails (0.1.8) elasticsearch (1.0.15) elasticsearch-api(1.0.15) and elasticsearch-transport(1.0.15)
The elasticsearch version is Version: 1.2.2, Build: 9902f08/2014-07-09T12:02:32Z, JVM: 1.7.0_65