Three of the Big Four carriers in the US have already rolled out Marshmallow to the HTC One M8 and M9 units on their network. So we can say the Marshmallow update for AT&T-branded M8 and M9s is already delayed.
Worse still, it has been revealed that the update has been hit by further delays. The revelation was made by the Taiwanese company's VP of Product Management Mo Versi on Twitter.
HTC One M8 & M9 AT&T owners - there's been a slight delay on M OS. We're in lab but looking at approval within the next couple weeks.— Mo Versi (@moversi) April 29, 2016
The reason behind the delay wasn't revealed, although given that HTC is claiming to get the approval in next couple of weeks, it's reasonable to assume that either the problem wasn't that big, or the company caught hold of it and sorted it out quickly.
It's been very late.. i have been waiting and this is really making me go out my patience... after paying such a hell lot of money on my phone, HTC is failing to give a MM update...
I've got marshmallow on a uk note 4. There is virtually zero difference.
Apparently there has been a delay for the note 4 also....