HCL Sametime server 11.6 was released. Official announcements will come soon.
Register for this official launch event on June 7
Although the upgrade from version 11.5 is the same as previous release, I created a simple Step by Step tutorial.
This is a companion discussion topic for the original entry at https://alichtenberg.cz/how-to-upgrade-hcl-sametime-community-and-proxy-server-11-5-to-11-6/