OnePlus One users have something new to look forward to: the Cyanogen OS 12.1 update, which is based on Android 5.1.1 Lollipop.

OnePlus is reportedly pushing out the Cyanogen OS 12.1 over the air to the first-gen OnePlus smartphone users.

According to an Android Police report, the update is currently making its way to only 2 percent of users but is anticipated to make its way to more OnePlus One users in the next couple of days. Therefore, those looking to download the OTA update may have to wait a little longer.

Alternatively, one has the option to download the Cyanogen OS 12.1 update manually.

The full update weighs 645MB and has the build number YOG4PAS1N0. It also brings patches for the Stagefright security vulnerability on Android, which enabled hackers to take command of an Android smartphone via a specially designed media file delivered through an MMS. OnePlus has already taken out a patch for Stagefright for its OxygenOS for both OnePlus One and the latest OnePlus 2.

"This update provides critical security fixes for your device to address recently publicized vulnerabilities on Android devices. As this is a sizable update, please allocate 20 minutes for the installation process and ensure your device is fully charged before proceeding with the install," states the update's notification.

There is also a smaller update weighing 304MB, which is available for users running Android 5.0 Lollipop. Whether you install the full or smaller version of the update, it will work on your OnePlus One smartphone.

Among the major changes the Cyanogen OS 12.1 update brings OnePlus One users is activating the home button in Chrome. The homepage's default search engine is Bing, so it seems the change is due to the Microsoft and Cyanogen partnership.

The complete Cyanogen OS 12.1 update can now be downloaded online manually.