Hi, I'm Jeremy Foo.
I write software to make lazy people lazier.

There might be times where you beta testers are not near the computer they sync their iOS devices with and you don’t have invites to testflightapp. So one of the ways to get your betas onto their phones without requiring a sync is actually by using the iPhone Configuration Utility.

Steps so you can tell them how to get your beta onto their device,

1. Launch iPhone Configuration Utility.
2. Click on “Applications” in the sidebar.
3. Hit cmd + o.
4. Navigate and select the IPA file that was sent to them. It should appear in the Applications list.
5. Connect their iOS device and select it under the “Devices” section of the sidebar
6. Click on the “Applications” tab
7. Navigate the list till you see your app and hit the install button at the right side of the row.
8. Voila.

Not so sure about the updating part but it should be as simple as replacing an existing IPA.