I wonder what is the longest running XMPP service without a restart.
I watch a few servers running Tigase but then I restart them from time to time for software update with new features or bug fixes.
One of them is im.flosoft.biz which runs on quite old Celeron 1.33GHz machine with 200MB memory. Serves approximately 800 online users and works well for 75 days already without a restart. This is a development version of the Tigase 5.1.0 branch but indeed, Florian pushes me to release it as another stable version.