The issue with the latest version of Android, version 6.0, also known as Android M and Marshmallow, is that so very few Android devices, even the newest, don't have it. Android M has been out for almost four months, and the issue is that, unlike other Android device manufacturers, HTC usually gives a deadline of when their users will receive the latest update. That deadline is 90 days for its newest (less than two years old) devices, and it kind of missed it. However, it was also said that the M8 and M9 would get their update at "the beginning end of 2015". This also didn't happen, but this is the latest on the Android M Version 6.0 Marshmallow Release Date HTC One M9 and One M8 on carriers like Sprint, Verizon, AT&T, T-Mobile, and US Cellular.
Generally, most of the latest news for the HTC comes from the Vice President of Product Management, Mo Versi. His latest tweet comes from less than a day before this writing, but it says that "HTC One M8 & M9 TELUS Owners! We have received approval and the Marshmallow OS update will be pushed out to your phones by tomorrow. Thanks!"
I have to admit, that isn't really a good sign that it will be coming soon, or at least not soon enough. I have an HTC One M9 with Verizon, and I just did the "System Update" and found that I am up to date, and I still have Android 5.1. Unfortunately, I would prefer Mo Versi to give a tweet saying: "the HTC Android upgrade is coming to the M8 and M9 now".
There is a report from Tech Radar saying that if you are in the United States and the HTC One M9 is unlocked, the Marshmallow update should be there. As it stands, I'm not certain how it will be rolling out on carriers like Verizon, AT&T, T-Mobile, US Cellular, and Sprint. One would think that there would be some progress on this, and that the upgrade for the HTC One M9 and the M8 should be showing up sometime this month or the next. That is, of course, an estimation.
Besides the HTC One M8 and the M9, other devices are supposed to receive their upgrade as well, including 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, and HTC Desire 816. The HTC One M7 is about two years old, so it will never get Android 6.0.
Speaking of older versions of the HTC One M series, HTC is planning on releasing their M10 very soon around Mobile World Congress, an annual event that occurs in Barcelona, Spain, devoted to mobile devices. The HTC One M10 (assuming that it will be called that) will more than likely come with Android 6.0 right out of the box.