I just updated the game and tried to load my previous save game, but none seems to be available, are the old saves removed / incompatible?

Seems like the save folder was moved. I don't know from where/where to on Windows, but on Linux it was ~/.godot/... but now it's ~/.local/share/godot. Try making a new save file with an obscure name and then search for it.

Thanks, I am runnning it on linux as well ... so this helps.