I have just updated to IOS 7.1 public release, and if I go to My app store for enterprise application and I try to download the application, this gives me error:
Cannot install applications because the certificate for example.com is not valid
But the same build is working for the previous versions of iOS up to iOS 7.0.6. Because it is new, I cannot find any information on the web.
As of iOS 7.1 AdHoc installations of any apps require an HTTPS connection (which will therefore need a certificate).
You can read a bit more about it here... http://www.hanchorllc.com/2014/02/01/ios-7-1-requires-ad-hoc-installs-to-be-over-https/
Trying to find more info on it now...
Heres a bit more from the Apple dev forums. https://devforums.apple.com/thread/221520?tstart=0