ASUS is working hard to meet its self-imposed deadline of upgrading several ZenFone devices to Marshmallow before the end of Q2 2016. We're technically in July and Q3 already, but we'll give the company a little leeway for almost-making it on time with these two new OTAs.

After the ZenFone Max and a couple of variants of the ZenFone 2 Laser, ASUS is now starting to roll out Android 6.0 Marshmallow to the ZenFone Zoom (ZX551KL) and ZenFone Selfie (ZD551KL).

The ZenFone Zoom is moving to firmware version 4.21.40.74 while the Zenfone Selfie is going up to 21.40.0.1692. Both devices are shedding a lot of preloaded apps (read: bloat) and gaining a couple of new apps from Google and/or Facebook. Here are the detailed changelogs for both phones:

Zenfone Zoom 4.21.40.74:

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.

ZenFone Selfie 21.40.0.1692:

"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)"

"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.

If you don't get the update notification on your phone and you don't want to wait for it to show up, you can download the file manually and install it from ASUS's support website at these two pages: ASUS ZenFone Zoom and ASUS ZenFone Selfie.