Users of HTC's One M8 and M9 are in for a treat as the company rolls out the latest Android update called "Marshmallow," Google's sweetest update yet.

HTC's Product Management Vice-President, Mo Versi, posted an announcement over Twitter how the Android devices, particularly the unlocked HTC One 8, will be rolled out in the next 24 hours.

"HTC One (M8) unlocked owners! Great news, all testing has been complete and the update for Marshmallow will be sent out within 24 hours. Thx," he wrote.

According to Techno Buffalo, the One M8 is not the first device from HTC to receive the new Android Marshmallow 6.0, as it has already been delivered to HTC's One A9 out of the box.

Meanwhile, One M9 and other HTC devices will be getting the newly-released upgrade before the year ends, according to a list of devices provided by Android Authority back in September.

This was confirmed by another post from Versi, in response to a query by a Twitter user on November 22, asking if the timetable for the rollout of the Android is similar for the HTC One M9.

Techno Buffalo says Google's Android Marshmallow has already been made available for other devices since October of this year, and updates become available within a 90-day period.

Among the devices already powered by the new Android Marshmallow, includes those from Google such as the Nexus 5, Nexus 6, Nexus 7 2013, Nexus 9, and Nexus Player.

The upgrade has also been confirmed for rollout in devices from ASUS (PadFones, ZenFone 2, ZenFone 2 Deluxe, ZenFone 2 Laser and ZenFone Selfie) and Huawei (Honor 7, Honor 6+, Honor 6, Honor 4X, Honor 4C, Honor 7I/Huawei Shot, P8, Mate S, Mate 7 and Ascend G7).

Aside from the A9, M8 and M9, other HTC devices that have been confirmed for the Marshmallow upgrade are the One M9+, One E9+, One E9, One ME, One E8, One M8 Eye, One Butterfly 3, Desire 826, Once 820 and Desire 816.

And because it is already live, the new Android OS is already getting some colorful reviews, which undoubtedly include relatively negative ones as well. 

In fact, one report from the IT Pro Portal considers the Android Marshmallow "no match for Apple's iOS9," because Apple has a smaller range of devices which can be given the updates.

"Since Apple has a much tighter control on the iPhone and iOS 9 ecosystems, it is able to update a much larger number of phones with few to no issues. Google on the other hand works with a large number of device manufacturers and carriers feel the need to differentiate their devices by preloading additional apps or even by skinning the latest version of Android," the report explained.