On steam there's a new update since the 11.3.17. On GOG there is still nothing about it.

They updated Humble yesterday, 2017-04-11, so its probably on its way here.

I was 60 percent into the game when it updated automatically. Now it seems to play in lower resolution and hangs when changing between fullscreen options. Is it possible to download the old version please?

Maybe later. For now all I can say is hat I'm on Windows 10 with ATI graphics. Managed to try out all fullscreen modes (the choice sticks after force-quitting and restarting) but all result in what has to be a 720p rendering of the 3D content (like characters and icons) instead of the 1080p I surely had before. I've seen the problem mentioned on the Steam forums so hopefully Revolution will fix it eventually. Although it looks worse I will finish the game like this for now. Remembered I have a download of the last version somewhere to use next time.

Aren't you using Galaxy? If so I believe you should be able to rollback to the previous build as long as you still have a compatible save.