If you have installed on your device Android N Developer’s Preview, you probably have been disappointed to learn that this is probably prevent you from getting the OTA-update on Android Beta program. At least, that was written directly to the download page.
Fortunately, journalists from Android Police appealed to the Google, to confirm this information, and it turns out that the warning was formulated entirely true. So you will still be able to receive OTA firmware after the system image.
If you join the Android Beta, you will get the same Developer’s Preview, as if stitched image. Moreover, according to a Google representative, Dave Burke, the company sends OTA for the full version, not an incremental update. So, the difference between the versions of the operating systems have.
Thus, if you want to get the OTA-update for your device after flashing the factory image, you simply need to register your device in Android Beta. When an update is available, you just have to install it.
Burke said that in the near future the site will be updated Android Beta.