Android 5.1 Lollipop updates are available on a number of Motorola devices including the Moto G, Moto E, Moto X 1st Gen and Moto X 2nd Gen. However, the update did not reach everyone. A disproportionate number of carrier subscribers are waiting for Android 5.1 Lollipop, even though the firmware is already available.
With Android 6.0 Marshmallow about to be released, this may very well be the last chance for carriers to roll out Android 5.1 Lollipop - if they are planning to do so at all.
Moto G
Like Moto X (2013) and Moto X (2014), the Moto G series is expected to receive the Android 5.1 Lollipop. So far, Motorola has released such update for the unlocked version of the original Moto G. So far, both the unlocked Moto G 1st Gen and Moto G 2nd Gen have been updated to the previous Android 5.0 Lollipop.
Moto E
Curiously, Motorola has already updated Moto E 2nd Gen to the Android 5.1 Lollipop. Verizon's version of the Moto E 2nd Gen has gotten the firmware updates as well.
In the meantime, the first gen Moto E has not gotten Android 5.1 Lollipop. The Moto E represents Motorola's budget line. In fact, the device is on sale for the modest starting price of $179.
Moto X 1st, 2nd Gen
Motorola has been quick with updating both the original Moto X and its successor to Android 5.1 Lollipop.
As of July, many Moto X 2nd Gen users have gotten their update via several major carriers including AT&T, Verizon and US Cellular. T-Mobile has also rolled out the Android 5.1 for Moto X 2nd Gen, but only for the Pure Edition.
In contrast, only AT&T has rolled out Android 5.1 Lollipop on the Moto X 1st Gen. However, the wireless service provider postponed the launch cycle due to unspecified issues. This happened late July, and there has been no further news from AT&T as of now.
Verizon's testing lab has received Android 5.1 Lollipop, according to Motorola employee David Schuster. Still, there is no word regarding whether or not Verizon is testing out Android 5.1 Lollipop for the Moto X 1st Gen.
Sprint has remained mum on whether their Moto X (2013) will be getting Android 5.1 Lollipop.