Nexus 4 has a 4.7″ 720p display, delivering 320 ppi. It is powered by a 1.5 GHz quad-core Qualcomm Snapdragon S4 Pro processor, featuring four Krait cores and the class-leading Adreno 320 GPU. In addition to the fast processor, the Nexus 4 also packs 2 GB of RAM and either 8 or 16 GB of internal storage.
Android 5.1.1 update for Nexus 4 is available via the OTA as well as the factory image. However if you are interested in custom ROMs, you can install the latest CM 12.1 custom ROM which will update Nexus 4 to Android 5.1.1. Follow the guide below.