Sony Xperia ZR was launched in June 2013 with Android 4.1 Jelly Bean. The 4.55″ display has a resolution of 720×1280 pixels. The 1.5 GHz Snapdragon S4 processor is quad-core. The Xperia ZR runs on 2 GB of RAM, with 8 GB of internal storage which can be expanded with a microSD card. Like the Xperia Z, this phone is dust and water resistant.
Sony Xperia ZR missed out on the official Lollipop update (Android 5.1.1) from Sony. However you can install CM 12.1 ROM running on Android 5.1.1 on Xperia ZR. You will lose the stock ROM but you will have the Nexus experience with CM 12.1. Follow the guide below.