Update: Looks like first up is a 4.49MB application update that is "a bugfix to let you install the latest system update successfully."
HTC is planning to roll out Marshmallow updates to the unlocked versions of the One A9 and One M9 within the next 24 hours. The company is certainly in the festive spirit, aiming to deliver some new features to consumers just in time for the public holiday. The former will be receiving Android 6.0.1, while 6.0 Marshmallow will be hitting the One M9.
Happy Holidays! Updates to the Unlocked A9 6.0.1 and Unlocked M9 6.0 will be able to be downloaded within next 24 hours! Enjoy :-)— Mo Versi (@moversi) December 23, 2015
It's positive to see the company stick to its guns and roll out Marshmallow to M9 owners before we head into 2016. Be sure to keep an eye out for the update to hit your smartphone and do let us know in the comments if you receive it.
Source: Twitter (Mo Versi)