I just upgraded form v1.17.102 to v1.17.105 and D1 savegames are working well. Thanks very much, maybe I'll finally play all the way through the original campaign after all these years!

Now of course I've found a couple of other problems. I'm not at home so I can't post a proper ticket to sourceforge but I thought I'd tell you about them anyway and in which campaign I encountered them. (I'll make tickets when I can)
-Descent 1: The reactors no longer fire at the player.
-Descent 2 Vertigo: Players are unkillable. Your shield can be reduced to 0 but after that you cannot die
-All modes: HUD text that should be red is now yellow (Guidebot messages, selected weapons in the minimalist HUD, etc.)
As always, thanks for all your efforts.