Earlier today Google has officially announced the launch of Android N for new Android smartphones. Soon after their announcement, HTC has make a swift announcement on the Android N firmware which will be soon available for certain HTC models which are THC 10, HTC One A9 and One M9. As the source code for Android N has to be distributed to manufacturers, it is likely that these smartphone will receive the latest Android N upgrade earliest on the next quarter this year.
However, older flagships such as One M7 is not scheduled to receive any further updates as stated on a reply from HTC USA.
Source : sogi