We have just found out that the iOS update 14.4 crashes the IceTV app and are working on it tonight to solve it and submit the update to Apple. They are usually quick to turn updates such as this around so if you can please hold off updating your iPhone or iPad until the update appears in a day or so.
my IceTV on the iPhone 12 is still not working. Can you investigate?
Can you post this as a support ticket. I'm assuming you have tried deleting the app and reinstalling it plus properly restarting the iPhone?
Not sure that it is relevant, but my iPhone 8 and iPad Air (3rd gen 2020) are not experiencing any problems with the IceTV app.