HTC confirmed that it will be pushing an Android 6.0 Marshmallow update to the One M8 a while back but has previously only said that it would be available "beginning end of 2015" - whatever that means.
Now it looks like HTC One M8 owners don't have to wait much longer as Twitter leak specialist LlabTooFeR claims that it will be available to European handsets in the next two weeks.
He also claims that there will be a Sense 7.0 update at the same time, with the phone not getting HTC's proprietary software as originally expected in August. HTC itself claimed that it would update the M8 with the latest version of Sense a few months ago, but that didn't happen.
Final M8 Android 6.0 and Sense 7.0 update for Europe will be available in about 2 weeks. It will be in build range 6.12.401.x ...— LlabTooFeR (@LlabTooFeR) December 2, 2015
The HTC One M8 is one of a number of handsets on the company's list for Android 6.0, but there is currently no news or speculation on when the other devices - including the HTC One M9 - will get the over-the-air patch.
If the M8 does get it in the next couple of weeks though, it can be safely assumed that the M9, at the very least, will follow soon after.
You can check out the current details on which HTC phones are expected to get Marshmallow in our handy guide here. It also details all other Android handset manufacturers and their plans to roll out Android 6.0.