HTC One, formerly known by the code name M7, is HTC’s flagship device for 2013. The device features a powerful quad-core 1.7 GHz Qualcomm Snapdragon 600 processor (APQ8064T), 2 GB of RAM, 32 or 64 GB of storage, a 4.7″ 1080p Super LCD 3 display with 468 ppi, a 4 MP “Ultrapixel” camera with an f/2 lens and large pixels, and a 2300 mAh battery.
CyanogenMod team are working on providing the latest Android updates for many devices. They have come up with CM 12.1 ROM running on Android 5.1.1 for HTC One M7. If you want to install this ROM on HTC One M7, follow the guide below.