The most convenient way for distribution of internal apps for a particular organization is Apple Developer Enterprise Program, which allows installing apps directly from web.

In pre-iOS 9 ages it was sufficient to confirm that you trust XYZ Ltd. developer and installation took place. In iOS 9 it has become a little more complicated.

When trying to install an enterprise app, you get this error message:

Untrusted Enterprise Developer
“iPhone Distribution: XYZ Ltd.” has not been trusted on this iPhone. Until this developer has been trusted their enterprise apps will not be available for use.

As you can see, this error message is not very helpful. Luckily the solution is very simple. Go to:

Settings -> General -> Profile -> XYZ Ltd. -> Trust “XYZ Ltd.”

Now you can install any app form XYZ Ltd. developer.

Vladislav Skoumal