My Acorn app is not opening since IOS 11 Installed yesterday

Restart the device and try again.

Delete the app, redownload it, then try.

Delete the app, redownload it, then try.

Redownload apps, music, movies, TV shows, and books from the iTunes Store, iBooks Store, and App Store - https://support.apple.com/HT201272

How to contact an app developer - https://support.apple.com/HT207959 - for problems running an app or problems restoring purchases

Here's Apple's official help document about this (mostly the same I already posted):

If an app unexpectedly quits, stops responding, or won’t open - https://support.apple.com/HT201398

I got in touch with acorn tv support and they replied almost immediately.

And they fixed the 11.3 update problem!

The new update may not show as one of your auto updates but if you go to the acorn tv app in the app store it will show an update. Apply it and everything will be fine.

Thanks Acorn!!