Define official, John stated multiple times that they have passed sprint
via the HoFo App
HTC One M9 Overview:
With a premium all-metal unibody, the beautiful One M9 doesn't stray away from HTC's gorgeous design tradition for its flagship line. For the first time in recent memory, we...
No. Each phone needs its own SIM card, then you have to use Sprint.com/activate to complete the swap. It takes 2 minutes.
Sent from my iPhone 6+
This isn't an official T-Mobile support site. Call, chat with them via their website or forums, or hit T-Force up on Twitter to get an actual answer from the company about your situation.
I use www.bestmnvo.com they have good info & research. Plus they on twitter, fb, google+