Android 6.0 Marshmallow is coming in a couple of months, but some manufacturers are still updating their devices to Android 5.1.1 Lollipop. Today Android 5.1.1 Lollipop is available for HTC One M9 on Verizon carrier.
The Android 5.1.1 Lollipop has already been rolled out to the international version of HTC One M9 as well as T-Mobile, AT&T and Sprint versions of the handset. The new update brings Stagefright fix and a number of other small bug fixes and performance improvements. The update will also give you support for a couple of more LTE bands including LTE bands 3 and 7 (1800 MHz and 2600 MHz). These bands will help connect to more networks around the world seamlessly while roaming.
HTC One (M9) Verizon customers! Received approval for L5.1 which will OTA out tomorrow. Includes Stagefright fix,Band 3 & 7 enabled -roaming
— Mo Versi (@moversi) August 19, 2015
As always, you might not see the update notification immediately. It may take some days for the update to reach your device.