Android 6.0, or Marshmallow as it is affectionately called, was released to the public in late 2015, however, it can take months before the manufacturers to release it on their own devices. HTC worked to get both the 2014 flagship HTC One M8 and the 2015 flagship One M9 ready for the update. We have seen the upgrade hit a little over a week ago for the One M8 and then last week there was an upgrade for the HTC One M9 on Rogers, Wind Mobile, Videotron and SaskTel carriers, although customers on Bell and Telus were left off the schedule. That is until today when Bell started pushing out the upgrade to its HTC One M9 owners. Please remember, this a rolling upgrade so you may not be notified right away, but you can always 'force' the software update by navigating to Settings -> About -> Software and check for any software upgrades. Below you can see that it is a 1.24GB upgrade and software number 188.8.131.52.
It is a little surprising it has taken HTC so long to upgrade the One M8 and especially the One M9 since their newest model, the HTC One A9, came out with Marshmallow already on the device. Looking at the One M9, this Marshmallow update brings about a few new features. As usual, the new operating system adds new and improved power management features and one in particular is called Doze...the OS can literally suspend applications that are being used infrequently. Those pesky power-consuming features that are not being used when your smartphone is idle with its lock screen, will Doze off.
AutoSync and location sensors are two prime examples - however, pick up your device and these features will be reactivated. You will see a complete visual overhaul, especially if the manufacturer has a light UI. Rather than relying on a manufacturer to add the option - the ability to control application permissions are now baked into Marshmallow. Google Now on Tap is also part of Marshmallow and this gives you the ability to ask Google for help with whatever is on your display. According to HTC there will be an overhaul and improvement in the camera software and the usual "performance improvements and bug fixes" that are always part of an upgrade.