I can't find any documentation on it - does anyone know how auto-updates are handled? Do you just release a new version and hope for the best or is there some sort of mechanism to force people to update?
Updates are submitted to the Windows Store, just as you would with any other Store app. After approval, they can be configured to trickle out and/or force install (when available). More information can be found at https://msdn.microsoft.com/windows/uwp/publish/upload-app-pa...
You can also create a "flight group" consisting of your test team and only push out more broadly when your internal QA passes. Check out https://msdn.microsoft.com/en-us/windows/uwp/publish/package... for details.