HTC has a pretty good comeback phone on its hands with the U11, even if its massive size and large bezels stick out a little in today’s skinny bezel-less landscape. The company was one of the first to start stripping away core features and moving them into Google Play, where they could be updated independently of a major firmware update.
HTC has proven itself to be one of the more forward-thinking Android manufacturers where updates are concerned, but being adventurous sometimes leads to issues. HTC was one of a few OEMs to temporarily shut down their Nougat update due to issues that only became apparent after the rollout had begun.
Bugs notwithstanding on the Nougat rollout, HTC got it out internationally after just 95 days, with it landing on the T-Mobile HTC 10 after 138 days. T-Mobile was also the first in the US to get Nougat out to the HTC One M9, taking another two and a half months to deliver that update.
By comparison, the Marshmallow update was all over the place (if generally very promising): the HTC One M8 Google Play edition was naturally very quick out the gate, followed a few weeks later by the Developer Edition of the HTC One M9 in December. Unlocked versions of the One M9 and A9 also got updated (to Android 6.0.1 rather than 6.0) in December and most carrier-branded versions in early January.
Times have obviously changed since the good old days of Google Play and Developer Editions, meaning HTC’s Oreo performance is probably more likely to match Nougat than Marshmallow. That gives us a date of around four and a half months for the HTC Android 8.0 update, putting it somewhere around December or January, depending on when exactly Android O officially drops.
Best case scenario: 4-5 months after Android 8.0 arrives (December 2017/January 2018)