The Galaxy Nexus was never officially updated by Google beyond Android 4.3 Jelly Bean. However, the phone continued to live thanks to the Android development community, which released AOSP based KitKat and later Android 5.0 based ROMs for it.
Now, to the rejoice of Galaxy Nexus users out there, the CyanogenMod team has started rolling out official CM12.1 nightlies for the handset. Keep in mind that CM12.1 is based on Android 5.1 Lollipop and not Marshmallow. Nonetheless, for a phone that was abandoned by Google in 2013, it is nothing short of amazing to run an OS version that was released almost two years after that.
On top of Android 5.1, CM12.1 also packs in a plethora of customisation and personalisation options that will definitely delight the few Galaxy Nexus owners still out there. Despite all the optimisations thrown in by the CM team, don’t expect the G Nexus to run Lollipop lag free and without any performance issues though. With only 1GB of RAM on the handset, you are likely to run out of free RAM with only a handful of apps opened.
Read: CyanogenMod 12.1 features walkthrough
Download: CM12.1 for Galaxy Nexus