"Better late than never" is almost never said with real sincerity, and such is the case with the latest build of Android for the T-Mobile Moto X. All three of the other carrier versions of Motorola's 2013 flagship have already received the latest version of Android: Sprint, AT&T, and even Verizon. Perhaps the fact that T-Mobile doesn't actually sell the phone has something to do with it - it's only available in a non-contract, unlocked "T-Mobile" edition at full price from Motorola.
Whatever the reason for the delay, at least some users of the T-Mo Moto X are now getting Android 4.4.4, some eight months after the release of Android 4.4.2. One user was kind enough to show us the over-the-air update message for the Uncarrier, which he received late Monday night. The jump from 4.4.2 to 4.4.3 and 4.4.4 includes quite a lot of bug fixes and security enhancements - we don't have the size of the T-Mobile update, but the other carriers have been in the 150MB range.
Because this update is coming from Motorola itself and not T-Mobile, you may or may not see the usual carrier practice of a staged rollout. In any case, those who have rooted or otherwise modified their phones might have trouble applying the 4.4.4 OTA, and may loose root if it's successful. Moto X users, if you're interested in even faster updates, there's always CyanogenMod - the T-Mobile Moto X has an unlockable bootloader.