Openfire keep disconnecting clients randomly

Hello - I’ve been running Openfire 3.6.4 for around 2 years now without any issues and just recently in the past 3 weeks users have been randomly getting disconnected via various clients (spark, adium, trillian, windows/mac).

I’ve been digging trrough the debug, error and info logs in /opt/openfire/logs and I do not see any correlation to the disconnects.

Java memory is fine, the server always shows around 11% of the memory used.

Any ideas?

Thanks