HTC has reportedly taken the next steps on its Android update roadmap for its older devices. A Twitter user located in Taiwan has posted the upgrade notification for version 9.0 (Pie) on their U12+. However, this has yet to be followed by reports of the same in other areas.
https://www.notebookcheck.net/HTC-U12-reportedly-updated-to-Android-Pie-in-Taiwan.426753.0.html