Trinity and VAIO have been pretty slow with releasing the Anniversary Update on their NuAns NEO and Phone Biz phones, blaming it on a Continuum bug that needed to be fixed first. It seems like these issues have been resolved now because Windows Forest is reporting that the update is now available.
There is, unfortunately, no news about the HP Elite x3 update, but seeing that other manufacturers are now updating their handsets, it is just a matter of time before HP follows.
The update delivers build version 10.0.14393.189, which means it isn't the RTM build. It appears these devices received an extra cumulative update to resolve the prior issues.
To check if the update is available for you, head over to Settings > Update & Security >Phone Update and tap "Check for updates". The update should start downloading.