There have been a lot of rumors about BlackBerry 10.1 for the T-Mobile BlackBerry Z10 floating around for several weeks, however, it does look like the official update is now available OTA.
If you were one of the adventurous types and installed a leaked build you may have to revert back to your original factory OS as you won’t see the OTA update if your leaked build is a higher version then the official release.
BlackBerry 10.1, at the time of this posting, hasn’t shown up on BlackBerry Link, so, updating OTA is the only way for now.
The full change log can be found on the T-Mobile website…