ASUS has now started rolling out the Android 6.0 Marshmallow OTA (over-the-air) update to the ZenFone Zoom (ZX551KL) and ZenFone Selfie (ZD551KL) smartphones. The ZenFone Zoom is moving to firmware version 4.21.40.74 while the Zenfone Selfie is going up to 21.40.0.1692.

"Android 6.0 Marshmallow"

The update brings all the Marshmallow goodies including Doze battery saving feature, run time app permissions, Google Now on Tap and lots more. In addition it also removes a bunch of bloatware from the devices that ASUS phones usually tend to come with. Here are the detailed changelogs for both phones:

"Asus Zenfone Zoom"

Zenfone Zoom 4.21.40.74 update changelog:

The apps listed below will no longer be pre-loaded once your device has been upgraded to Android 6.0 (Marshmallow). Thanks for your support.
(1)ASUS Backup
(2)Google Play Books
(3)Google Play Games
(4)Google Play Newsstand
(5)Google+
(6)ZenFlash (Can be downloaded from Google play)

Add new features and new apps:
– Google Calendar
– Google Messenger
– Facebook
– Facebook messenger
– Instagram

Remove Asus Email, Asus Calendar, Asus Messaging, Asus Browser and Asus Music after Factory Reset. You could use Gmail, Google Calendar, Google Messenger, Chrome and Google Play Music for relevant services

Multi-user and SnapView will not be supported. If you wish to continue to use multi-user, please keep using current account.

"Asus Zenfone Selfie"

ZenFone Selfie 21.40.0.1692 update changelog:

“The apps listed below will no longer be pre-loaded once your device has been upgraded to Android 6.0 (Marshmallow).Thanks for your support.
(1)ASUS Backup
(2)Mirror
(3)Remote Link
(4)Party Link
(5)PC Link
(6)Photo Frame
(7)What’s Next
(8)ASUS MyFrame
(9)ASUS MyWater
(10)Omlet
(11)Data Transfer
(12) Snap View
(13)EZ 訂 (TW SKU)
(14)Dr. Eye (TW SKU)
(15)Yahoo 購物中心 (TW SKU)”

Also Read:  Samsung Galaxy S6 and Galaxy S6 edge User Manual (PDF)

“Add new features and new apps:
– Google Calendar
– Google Messenger
– Motion Gesture
– Camera: Pano Sphere Mode”

Remove Asus Email, Asus Calendar, Asus Messaging after Factory Reset. You could use Gmail, Google Calendar, Google Messenger for relevant services.

The update does not support APP2SD, so ASUS recommends you to transfer all your apps to the internal storage before updating.

The OTA update is rolling out in stages, so it may take a few days before your device pops up the notification for you. You can always check for the latest update manually by heading to Settings > About phone > Software update.

If you don’t want to wait for the OTA update, you can download the full firmware update from ASUS’s official website at these two pages: ASUS ZenFone Zoom and ASUS ZenFone Selfie and install it manually.

Source: ASUS Forum ZenFone ZoomASUS Forum ZenFone Selfie