So the story goes anyways. According to Mo Versi, who is the VP of Product Management for HTC, the Sprint variant of the HTC One M9 is on track and approved to receive Android 5.1 just in time for the long holiday weekend. Sprint hasn’t announced anything, nor have they updated the devices software update page, nor has HTC made a change to the Sprint software page, but Mo knows what is going on and hasn’t made a false update announcement before.
HTC One (M9) Sprint Owners! We have received technical approval on Lollipop OS 5.1 which includes camera improvements. OTA to start on 7/1!
— Mo Versi (@moversi) June 29, 2015
Like all other updates, you can expect it to roll out in waves with the first batch landing on July 1st. That could be as early as midnight ya know. You will want to make sure your device is charged well over 50%, you have a solid Wi-Fi connection and some time for the OTA to download and install.