HTC showed the One M9 at the recent Mobile World Congress 2015 to shift the focus temporarily from its existing One family. Mo Versi, VP of Product Management at HTC America noted that the Android 5.0 Lollipop update is set to begin seeding on March 10 for One (M7) owners on T-Mobile network.
HTC One (M7) T-Mobile Owners! We've received technical approval on the L OS and OTA will start on Tuesday. #htcadvantage— Mo Versi (@moversi) March 7, 2015
Versi shared on Twitter that the Lollipop build has got the technical approval. The update will certainly package all the major Lollipop goodies such as refreshed recent apps menu, notifications and system wide tweaks.
The Lollipop OTA update will commence from March 10 onwards and can be downloaded over the wi-fi or cellular network.Source