We're looking into this now, seems to be a backend thing. WIll ping here once it's fixed.
T5_k said: There was no mention of compatibility of the 3.5.3 game version with the 3.5.2 version saves.We never guarantee backwards compat with older saves.
Can I update and play my 3.5.2 save or should I postpone the update and stay on v3.5.2 to finish my game?
With a smaller patch like this, it's more likely to be fine. However there is a rollback branch and I'd advise backing up your save before giving 3.5.3 a try.