A few days ago, HCL Sametime and HCL Sametime Premium 12.0.1 were released. The installation is basically the same as for version 12.0, but I modified my guide.
The upgrade is also very simple, so you can check out the guide I prepared.
So you can get started.
This is a companion discussion topic for the original entry at https://alichtenberg.cz/hcl-sametime-12-0-1-how-to-upgrade/