How can I prevent the SimpleMDM profile from being removed from a device?
The SimpleMDM profile can generally be deleted from a device at any given point. When this profile is deleted, SimpleMDM loses the ability to manage the device and the user loses all apps and configurations that were provided by SimpleMDM.
Apple allows for one exception to this rule. If a device is enrolled using the Apple Device Enrollment Program (DEP), the administrator can disallow removal of the profile.
Here are two helpful resources on DEP:
Choosing an Enrollment Method
Explained: The Apple Device Enrollment Program
Once an Apple DEP account has been connected to SimpleMDM, the option to prevent the removal of the MDM profile will be shown on the DEP Account Settings page labeled as "Allow MDM removal by user".
Note: For devices that have been provisionally added to DEP, meaning they were activated prior to being registered in DEP and were later added via Apple Configurator, Apple enforces a 30-day window after enrollment during which the MDM profile can still be removed by the device user. If provisionally enrolled devices are not unenrolled at any time during this window, the MDM profile will become unremovable.