Discovery app won't run on phone

Just been told my 4 year old, Android 5, phone is too old to run the Discovery App. This would be fine if there was any other way to interact with half their options - web site? hello!. I haven't come across *any* other app which won't run on this phone. Every other banking app works fine. 1 in 4 Android phones runs Android 5 or less!

Come on Discovery, this is a shocker!