During Google's recent press event, the search giant confirmed that it will begin distributing the new Android 6.0 Marshmallow OS to its co-branded Nexus devices. The rollout does not include devices from other manufacturers. However, it does mean that the Android M code will go to the Android Open Source Project (AOSP), allowing device makers such as Samsung, LG, and HTC to start developing OS updates for their own devices.

HTC has been vocal when it comes to Marshmallow updates for its recent HTC One M8 and One M9 handset. Jason Mackenzie, president of HTC America, recently tweeted that Android 6.0 is coming to a handful of HTC flagship phones, including the One M8 and the current generation One M9. It is worth noting, though, that the original One M7 is not in the list, indicating that smartphones released over two years ago will not receive the latest OS updates.

As users can see in the photo above, the tweet confirms that the listed HTC models will see Marshmallow updates "before the end of 2015." It means the software upgrades will start rolling out before the end of the year, but will probably not reach all users of said devices by then.

HTC usually sends out OS releases outside the United States first, then eventually move stateside. However, the early confirmation came from the American division, suggesting that HTC One M8 and M9 units under US carriers could receive the updates anytime between now and early January next year.

Earlier reports mentioned that the HTC One M8 Google Play Edition is slated to get its Android 6.0 Marshmallow update by the end of this month. This is not entirely surprising as the Google Play Editions of handsets from other manufacturers had received Android 5.0 early, too.

While waiting for the upcoming Marshmallow upgrade, HTC One M8 and M9 users are stuck with earlier versions of Android Lollipop as the Taiwan-based company will reportedly skip version 5.1.1 and head straight to Android 6.0. Major U.S. carriers AT&T, Sprint, Verizon and T-Mobile have not announced plans to release Android 5.1.1 on both HTC devices.

The company's 2015 flagship was running Android 5.0 Lollipop out of the box when it began shipping and is currently only upgradable to version 5.1. Its predecessor, the HTC One M8, first arrived Android 4.4.2 KitKat and is now upgradable to Android 5.0 Lollipop.