Connection reset by peer in 6.8 ES with 6.1.4 client

Often we are seeing "Connection reset by Peer" after migrating to ES 6.8. We are still using ES 6.1.4 client. It recovers, but often there is Connection reset by Peer.

Any solution or how can this be debugged.

I would recommend upgrading to the 6.8 client and see if this makes a difference. You should always use the same version of the client as the server. There are quite a lot of changes that have gone in between 6.1 and 6.8 which could cause problems.

Ok, planning on upgrading to the 6.8 client. However, what other reasons could cause this issue

Could less number of available thread can cause this or how can i go about root cause this .thanks