ASUS is already seeding the Android 6.0 Marshmallow update to the owners of the ASUS Zenfone Selfie (ZD551KL). Last month, ASUS did send Marshmallow updates to ASUS Zenfone 2 Laser and Zenfone Max owners.
The update will no longer App2SD activities meaning your apps can no longer be transferred to your microSD card. Please move all apps to internal storage before downloading the update. It will also remove a lot of bloatware, here are the following app that will no longer appear once your phone is updated.
12. Snap View
Apps like Google Calendar and Google Messenger will be loaded as part of the update. The file is quite big – 1.63GB so make sure that you are connected to a stable WiFi connection and have sufficient battery as well.