I am sorry, I did no get this information in the first post, just read the changelog.
But since I am not always watching the forums, how can I be sure that a atch does not kill my save games? Is there any option? Disabling updates in Steam does not work, it will enable itself after a restart and will then update.
Copy your entire CK2 folder to another folder - then launch the game from that folder (not steam, obviously).
By the by, original post says:
All v1.10x save games should be fully compatible.