I do seem to recall that for patch 4 I saw a warning screen, explaining that old saves would become obsolete, and how to continue with the unpatched version. This time I saw nothing, it was installed automatically without any warning or opt-out possibility. So I figured patch 6 would be compatible.
Patch 5 loaded also while I was in a game and I could continue it.
Not so with my current save, unfortunately. It sucks because I had gotten quite fond of the Karlagh as PC. But I don't think I'll start all over again.
