never ever trust dev/game saying save now
I'd say not to trust any
unfinished game to retain save compatibility between versions. This applies to all games that are in alpha, beta or even Steam's early access, regardless of the game engine used. But, most AVN players weirdly insist on not replaying from the start even if the dev made the game work better changing things under the hood.
AE S2 will be an unfinished game until MrK says "That's all folks". Let me repeat something I told in this thread earlier: MrK told me that AE will have
two seasons. Not three seasons like (non-Steam) RTP had. Of course, it might change if he wants to keep on making AE.