With iOS 9.3 loaded, and an MDM in use, employers are able to prevent employees from installing or even just testing out certain apps. And these iPhones can also be controlled by the IT Manager in terms of how often notifications are received, and what they look like when they are received. Besides controlling what apps can be loaded onto company owned iPhones, certain apps (including system ones) can be hidden at the discretion of the head if the IT department.
To enable this control over employees' iPhones, the IT Manager needs to use a server powered by OS X, and run Profile Manager on the company owned iPhones. This control is new to iOS and starting with iOS 9.3, it gives corporations more power over company-owned iPhone units.
source: Apple (.PDF) via @stroughtonsmith, TNW