The One M8 GPE doesn’t have HTC Sense UI and instead, it runs on the Stock Android platform. There is still a presence of some HTC software in the handset in order to support certain features like that of the HTC Photo Edit to be used with the Duo camera. Owners can also download the HTC Sense Apps from Google Play.
The GPE version of the One M8 was discontinued by HTC on January 2015. In the beginning, the HTC One M8 ran Android KitKat v4.4.4 out of the box. The One M8 GPE received the Android Lollipop update merely 5 days after it was launched on the Nexus devices.
This made HTC one of the first phone manufacturers to receive the Android Lollipop update. As a result, it should be expected that the standard One M8 from HTC will take some time to receive the new 6.0 Marshmallow update, but it should be coming soon to the GPE variant.
Meanwhile, with the Bluetooth certification, it shouldn’t be too long before the standard variant of One M8 receives the Marshmallow update.
Stay tuned for more information and details regarding future updates for HTC One M8!