You should fix your app. Just because Apple "broke" it, doesn't mean they care. The only person who cares enough about your app is you. Don't wait for someone else.
Technically the app isn't really broken, it's just outdated. Apple updated their software, it's not their fault if some app developers didn't do the same.
It sucks. I have to use Gatherer for all of my advanced searches now and it's just not even near the same.
Technically I just purchased iPad Mini for my wife and it came with iOS 10.3 becasue iOS11 sucks big time. Makes you both wrong, sadly.