HTC One S is the smaller version of the HTC One X. It features a 4.3″ qHD Super AMOLED display with a resolution of 960×540. Powered by a Snapdragon 400 quad core processor clocked at 1.5GHz, it has 1 GB of RAM and internal memory of 16 GB. When it was released, it ran on Android 4.0.3 ICS.
HTC have confirmed that only the flagship devices and their variants will get the official Lollipop update. But owners of other devices need not worry. If you want to update your device to Lollipop, there are plenty of custom ROMs available. CM team have released the official nightly of CM 12.1 ROM that will update the device to Android 5.1. Follow the guide below to install this ROM on the HTC One S.