t-mobile tuesdays stopped working on my iphone 6s

I have the same problem with a Samsung Galaxy S7 Edge, Android 8.0. I have a lot of apps on my phone. I get a T-Mobile Tuesday message stating it needs to be updated to Android 9.0 and that is not available

for my phone.  Interesting how all the other apps including an T-mobile app to pay my bill, works perfectly on my phone except something as simple as knowing if I can get 10% off on a pizza and similar other deals.  Ridiculous

Ken