The Android Oreo 8 update is likely to be pulled to HTC 10. The update was released to HTC 10 last week over OTA as well as RUU download. But the RUU link has been taken down and the users are reporting that they are not receiving OTA either.
The users who have manually installed Oreo on HTC 10 are reporting battery issues and other problems. So it looks like the OS update is not yet ready. And there is no official information on when the update will be available again