Announcement of pre-release versions of Android also bring updates about the factory images as they become available for users to download. With Android N, Google has brought new updates on the table. According to Google, Android N, the Android N Developer Preview can be installed in two ways.
The first is that usual factory image process and the second is a new and a much simpler approach which is to enrol in the Android Beta Program. This will allow users to receive seamless over-the-air updates to receive updates along to the latest beta versions of Android N.
According to the official portal:
You may remain in the Android Beta Program beyond the N release to preview future Android N maintenance releases (MRs). If you choose to do so, you will automatically get an OTA update to pre-release versions of the MRs as they become available. At the end of the program, you will begin to receive regular public updates.
You may opt-out of the program at any time to return to the stable, public version of Android. Note: If you opt-out when your device is running a beta version of Android, all user data on the device will be wiped.
After Gmail Authentication, it shows the devices that you own and can receive the N update
The device enrolment process is simple. Select the device from the list and click on Enroll Device.
Currently, the supported devices are:
Nexus 6, Nexus 9, Nexus 5X, Nexus 6P, Nexus Player