HTC operates a little different from other device manufacturers as it attempts to achieve upgrading its devices that are less than two years old with the latest version of Android within 90 days after the rollout. These 90 days is a target, and yes, it doesn't often succeed at this. In fact, it has been about 90 days since Android Marshmallow has rolled out, it the company went on record last fall saying that Android M would be available to both the HTC One M8 and the latest flagship, the HTC One M9, at "the beginning end of the year". This is what is currently known about the Android M Version 6.0 Marshmallow Release Date for HTC One M9 and One M8 on carriers like Verizon, AT&T, Sprint, T-Mobile, And US Cellular.
According to Pocket-Lint, there are some reports of M9 updates starting in Asia, and there was a recent tweet from Mo Versi, the Vice President of Product Management, on January 15 that promised the upgrade to the HTC One M9 on Monday, January 18th. Mo Versi is the HTC spokesman when it comes to the release of upgrades on HTC devices.
Again, this is a target date, as I am an HTC One M9 user, and I just checked my phone for a system update, and I don't have Android 6.0 as yet. Granted, I am with Verizon, so it might be possible that my update is delayed as certain United States carriers like Sprint, T-Mobile, AT&T, and US Cellular can often receive the upgrade before others. Also, the tweet above seems to refer to "Sasktel, Rogers, Wind, and Videotron HTC One M9 owners".
A recent tweet at HTC UK has promised that "we began rolling the Android 6.0 Marshmallow update to the One M8" as well as "it'll be coming to the One M9 soon, too". This tweet happened on January 19th, so UK HTC One M8 users are presumably enjoying their upgrade now. Considering that the M8 was a model of smartphone from two years ago, it seems odd that it got Marshmallow before the M9.
That tweet took place in the UK, which means that Marshmallow can't be too far from coming to the United States, assuming it hasn't arrived already at this time of writing. In other words, that update for the M8 and M9 is probably right around the corner for those in the United States, so the wait shouldn't be too long.
Here is a list of other HTC devices that are scheduled to receive the Android upgrade.
- HTC One M9+
- HTC One E9+
- HTC One M8
- HTC One E9
- HTC One ME
- HTC One E8
- HTC One M8 Eye
- HTC Butterfly 3
- HTC Desire 826
- HTC Desire 820