Magisk probably came to the public’s view when it gave people who were playing Pokemon GO an alternative to going stock from a rooted device. Niantic had started strict implementation of its “no root” policy, and Magisk was just the tool to get you root access when you need it, but go back to stock when playing Pokemon GO. Now the tool has been updated as it preps for multi-ROM support.
What Magisk does is actually as simple as it is phenomenal. Magisk will let users gain root access to a phone or tablet, and then also give them the ability to unmount those changes – basically “unroot” on the fly – when the user needs to do something that requires stock settings like doing an OTA update, using Android Pay, or yes, play Pokemon GO, as all of these require an unmodified /system partition.
The version 9 update to Magisk brings a new system called “xsetprop” as a new way of bypassing Google’s SafetyNet API. The V9 update also improves the Magisk Hide feature, which is another way to bypass SafetyNet on your device.
As a caveat, Magisk developer “topjohnwu” says that the phh superuser – the root manager app that works nicely with Magisk – must be updated to version r266-2 or better so that it works with Magisk V9. In case you are using something older, it is recommended that you update phh superuser first before updating Magisk.
SOURCE: XDA