Received the migration text for my SWAC account.

I've had/have a SERO/SWAC with Pandora Premium and Hulu on us account(2 lines) for over 18 years and I got the migration text in June stating that my plan will be changing after July 13th. One of my lines I'm currently on month 16 of a 24 month promotion for a phone upgrade. My billing cycle started over on August 27th and my bill populated today. On my bill nothing has changed and in the app I'm still showing an Advantage plan. Is there a chance that my plan isn't changing? Should I reach out to Tmobile or consider myself lucky my plan hasn't changed?