The Android 5.1 Lollipop update for Google's Nexus 6 smartphone under T-Mobile is now being rolled out.

However, the Android 5.1 Lollipop update is labeled as LMY47M, which is another build compared to the software being rolled out for other devices.

Since Google's official announcement of the new version of its mobile operating system last week, there has been confusion relating to the build number of Android 5.1 Lollipop.

The first over-the-air update for Android 5.1 Lollipop, which was released a few days ago, featured the build number LMY47D as it was pushed out to international smartphones and tablets. However, just a few days later, when Android 5.1 Lollipop was revealed to be the operating system to be included in the Verizon Nexus 6, a new build number LMY47E was stated on the official page of the Nexus Factory Images.

There have been no noticeable differences between the Android 5.1 Lollipop's LMY47M build on the T-Mobile Nexus 6 when compared to the other versions.

According to T-Mobile, the update to Android 5.1 Lollipop will have all the new features that would normally be in the update, including the Device Protection feature and several fixes to the stability of the operating system and known bugs in Android 5.0 Lollipop. In addition, the update also unlocks the VoLTE feature for T-Mobile's Nexus 6, and according to some users that have already updated, users will also be allowed to connect to the 700 MHz spectrum of T-Mobile.

The Device Protection feature helps users safeguard their devices if they are lost or stolen. The lost or stolen smartphone or tablet will remain locked until users sign in with their Google account, which prevents anyone else from accessing its contents even if the device undergoes a factory reset. The feature, if it sounds familiar, is similar to Apple's Activation Lock feature that was introduced in the iOS 7.

While the cause for the different build numbers is unclear, T-Mobile Nexus 6 owners can now check for updates on their smartphones to bring their smartphones to Android 5.1 Lollipop. The update will require free storage space of 409MB, so users should make sure that they have enough space for the update before initiating it.

The update can be accessed by going into the Settings of the Nexus 6, tapping the About Phone option and then on System Updates. Tapping on Check now will then see if the Android 5.1 Lollipop is already available to be downloaded and installed.