It looks like Google is rolling out the new Android 7.0 Nougat to those that has signed up for the developer preview beta program first before they released it to the rest of the Android users.
Devices that were running the developer preview beta program have been receiving the new Android 7.0 Nougat update according to Android Police. We have not heard from Google yet but some developers have been reporting that they have already received the update.
Besides the new OS, the new Nougat will also come with a few new features that will include new emoji, new features as well as a few updates. As for the rest of us, Google did say that they will start rolling out the update in the next few weeks so the wait should be over soon.
Nexus devices after the Nexus 5 will all be getting new Android 7.0 Nougat update.