Though it is slow but HTC is releasing Nougat update to their top devices. Recently HTC 10 has started getting the Android Nougat 7.0 in Hong Kong with the update version of 2.41.708.3 that needs 1.23GB file download. The update offers Nougat 7.0 including the Android security patch for January along with some system improvements.
If you have HTC 10 and gonna use Nougat for the first time, I would suggest you to get familiar with the features you are about to get in you phone, this post tells you about the best included features in Android 7.0 Nougat.
If you still haven’t received the update via OTA, go to settings and tap on About device. And go to System Updates, it will automatically start searching whether the update is available or not. You might need to follow this step couple of times.