The ZenFone Max isn't just good enough to star in a series of speed rapping videos, it's also great if you want a phone that lasts for two days straight thanks to a hefty 5000mAh battery. This update that it should start receiving OTA today is version WW_18.104.22.168. It pushes the device up to Marshmallow with all of its features (Doze mode, per-app permissions, Now on Tap, and so on) and also removes some of the redundant apps that Asus had preloaded on the Max.
Notably gone are Asus Email, Asus Calendar, and Asus Messaging. Given the criticism that the company received for its super bloated software with tons of duplicate apps and useless preloaded junk, it's nice to see it trimming the fat and leaving the user with the essentials.
The only warning is that APP2SD won't work with Marshmallow, so you'll have to move your apps from the SD card to the phone before upgrading. Good thing you'll have more internal space then.