Since the release of the upcoming version of Android, M, forums have been flooded with threads regarding the availability of the particular software.
It is a known fact that the 2012 Nexus line-up, including Nexus 4 handset and Nexus 7, 10 tablets have been discontinued from the company itself, thus emptying the lower-price point slot and simultaneously paving the way for newer devices. Though there was not any official mention about the compatibility of the next generation Android with the 2012 season.
Developers rocking a Nexus 5, 6, 9 have already received their preview, but there is no option for the older ones. Though, various users by digging in the Android Open Source Project, have spotted a number of mentions referring to the 2012 Nexus line-up, which primarily suggests that the latest version of Droid will be hitting the specific devices.
As Kitguru has correctly written in a blog post, a report from last month on The Little Green Dude mentioned that the 2012 devices were included in the AOSP, though some more tech-savvy Reddit users have pointed out that the AOSP tags devices that have been officially discontinued from receiving a newer software version. Hence, unless Google (NASDAQ: GOOG) starts monitoring AOSP more carefully, it cannot be a reliable source for concluding whether a device is updatable or not.
Based on the above it is highly unlikely to see the 2012 line-up going for an M update – we should not rule out the possibility though. Nevertheless, as soon as M starts rolling out to all users, developers will be able to develop their own ROMS, which you can use on your device, regardless if Google has you in or out. We believe that by early September Google will issue an official statement, thus letting us know about the situation.