Some time ago Google officially revealed Android 6.0 Marshmallow, their next generation of Android operating system. Android 6.0 brings lots of features, improvements and fixes over Android 5.0 Lollipop. You can read all about Android M, including new features and detailed changelog by clicking here.
Now OnePlus team has revealed Marshmallow upgrade schedule for OnePlus devices. According to OnePlus, their flagship phone OnePlus One is getting Marshmallow upgrade in the first quarter of 2016 and OnePlus 2 is also getting the Marshmallow upgrade in Q1 of 2016. However the latest update for OnePlus 2 includes new API for the fingerprint sensor.
The company is also trying to upgrade OnePlus X to Marshmallow as soon as possible, however they had now revealed any schedule for the Marshmallow update.