Hey gujs!
If you've put the old save in the AHITR/Game/Saves folder, and nothing syncs in game, you might might need to make a dummy save first (Just starting the game and making a save) if not put the save(s) into the Renpy folder in your Roaming folder might help. To do that:
Press Windows key + r
appdata in the search field
Roaming
Renpy
AHITR
and place your 7.10 save(s) in there. (and in the sync folder if you wish)
Going forward you shouldn't have to do it manually as saves should carry over automatically.
Hope this helps!