How to distribute internal app

I am a software developer for a water and waste water utility that has approximately 35 employees.

I am creating an Android / iOS app that will be used internally only by our employees.

What is the best way to distribute this on iOS? It is important that employees get updates, and it is also important that the app is not publicly available in the app store.
Perhaps you can go with TestFligth, the Beta Tester Program. I had tried to uppload an App to a circle of health care profesionals, the app was rejected for "Minimal Functionality", hoever 4 days after it was accepted for the Beta Program (TestFligth), this generates a http link that you can probide to anyone (aka Beta Testers), there's no more need to include UDIDs of their devices anymore on those releases, they just click on the link in Safari, and they download your app (first it will install the TesFligth Apple app).
Note that the link will be valid for 3 months, after that you'll need to upload another version.

Alejandro
How to distribute internal app
 
 
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