Android Marshmallow 6.0 will hit some HTC smartphones soon. The company has given the technical approval for two of the US carriers ( T-Mobile and Verizon) to deliver the Marshmallow update to HTC One M8 device. So the update is now rolling out to the HTC One M8 users in US through T-Mobile and Verizon carriers. US users already received the firmware update back in December, now the Marshmallow is completely available as official .
The update is currently available only for T-Mobile and Verizon HTC One M8 devices and the other HTC devices like One E9, One ME, One M8 EYE, One E8, Desire 826, Desire 820, Desire 816 and Butterfly 3 are scheduled to receive the latest firmware. But AT&T is still waiting for technical approval from HTC. Once they get the approval , they will roll out Marshmallow update.