The admin of the Asus ZenTalk forum has recently posted a list of Asus devices that are expected to be upgraded to Android Marshmallow later this year.
* PadFone S (PF500KL)
* ZenFone 2 (ZE550ML, ZE551ML)
* ZenFone 2 Deluxe (ZE551ML)
* ZenFone 2 Deluxe Special Edition (ZE551ML)
* ZenFone 2 Laser (ZE500KG, ZE500KL, ZE550KL, ZE551KL, ZE600KL, ZE601KL)
* ZenFone Selfie (ZD551KL)
* ZenFone Max (ZC550KL)
* ZenFone Zoom (ZX551ML)
Asus is slated to roll out Android Marshmallow update for the aforementioned devices starting on the second quarter of this year.
The admin who posted the device list also pointed out that if users restore to factory defaults after the said update, ASUS Calendar, ASUS Mail, and ASUS Messenger will no longer be the default apps, and instead will be replaced with its respective Google counterparts (Google Calendar, Gmail and Google Messenger).