Now that the next version of Android actually has a name, manufacturers are starting to announce which of their devices will get the next version of Android. Google has been releasing developer previews since March, for Android N - now named Android Nougat - so manufacturers have had their hands on the code for a little while now. HTC was the first manufacturer to come out and confirm which models will be updated to Android Nougat, and to no surprise, they include the HTC 10, HTC One A9 and HTC One M9. Their last three flagships from 2015 and 2016.
As expected, HTC didn't mention when these three smartphones would actually see the update to Android Nougat, especially given the fact that Google hasn't pushed out the final release yet - heck there's still another developer preview left to be sent out. However, HTC has been one of the faster OEMs when it comes to pushing out updates for their smartphones. That's primarily due to their move into a more stock Android experience, which is prevalent on the HTC 10 announced earlier this year.
Android Nougat is a fairly large update, even though it looks to be fairly small in terms of new features coming to the platform. Google has done a number of interface changes in Android Nougat, which can mostly be seen in the lock screen, notification shade and settings. Google has also added a slew of new features, with the most popular one being Multi Window. A feature that many had been begging Google to add for years. Android Nougat is slated to be launched in the third quarter (that's sometime between July 1st and September 30th) and with that new version of Android there will also be new Nexus devices. Which the specs for both have leaked out recently, leaving very little in terms of surprises.
It's likely that most flagships from 2015 and 2016 will be upgraded to Android Nougat. However, HTC is the only one that has put out information about these updates right now. So if you own a flagship from Samsung, LG, Motorola, or another company, you'll have to sit tight for now.