I was not able to tell what was resend and why. I increased number of data which is logged during resumption of stream to be able to find root cause of this issue when it happens on newer build.

%eric I've created build of Tigase XMPP Server with changes required for further analysis of this issue. Could you update tigase.org (t2.tigase.org and t6.tigase.org) to newest versions of Tigase XMPP Server?

When you finish with updating tigase.org installation please reassign this task back to me.

Updated to b4222.

After analysis of logs from new version I support there is an issue with packet counter either on client or server side. To be able to detect where is a problem I increased number of data being logged.

Updated due date - waiting on data which will be gathered from server when issue will occur

Today, after next logs analysis I identified case in which this issue appears. It is caused by the fact that Jaxmpp2 is not resetting H counter to 0 when stream resumption fails.

%bmalkow is now aware of this and will fix this issue in separate task.