Thanks for clarifying. Requests generated for the app will no longer include that header which should hopefully prevent the crashing issue. But it’s possible there will still be compatibility issues. In the meantime, you can try out kitch (development branch of the app) if you are still having issues: https://itchio.itch.io/kitch-setup
The other changes will likely require more involved changes to how games are launched, I’ll probably have an update for that sometime in the near future.