HTC is all but dead these days, with the company only choosing to release two or three smartphones a year. The Taiwanese company's last true flagship phone was the U12+ that was released about two years ago, and the phone remains on Android Pie; without any hope for Android 10.
The U12+ ran Android Oreo at launch and received the Android Pie update in August last year. Since then, though, the U12+ hasn't received any love, and is yet to get anything Android 10-related; not even a beta.
That doesn't look to be set to change anytime soon either, if word from the company is anything to go by:
Regarding your question, the HTC U12 latest update available is the Android Pie (9.0). As far as we know, none of the HTC phones have received the Android 10 update and there is no information on when this update will be released or if it's going to be even released.
So, there it is, HTC U12+ owners. There's no release date for the Android 10 update, and it's unknown if the phone will get the update at all. It's sad to see one of the biggest smartphone brands at the start of the last decade turn into a shell of itself, but it is what it is.
Source(s)
Reddit via PiunikaWeb