If you are running Sametime V11 or earlier and want to upgrade to Sametime 12, you have two options. They start from scratch with a clean install (sometimes it’s worth it) or migrate existing Sametime to the new Sametime 12.
I have prepared a short guide on how to migrate the contact list (vpuserinfo.nsf) of your users and I have also added the option to convert from native Domino Directory to LDAP, which is a condition for migration to Sametime 12.
This is a companion discussion topic for the original entry at https://alichtenberg.cz/how-to-migrate-older-sametime-to-hcl-sametime-12-guide/