All post 0.4 saves should work without problems. Saves are stored in the browser cache.It's annoying that you can't use old saves I'm not gonna replay this especially since I spent so long getting the multiple routes. I liked it the first 5 times now its frustrating to scroll through shit I've already seen. I feel kinda weird about complaining about something I didn't pay for but I think I'll wait for longer to play this again.
Check if you are using the browser in incognito mode or if your browser is set to clear cache on exit. To avoid this kind of problem, I recommend everyone to use the save to disk option.