"Your browser is currently unsupported" BYOD portal - ISE 2.4 U14

[phake]

We've been noticing that any new iOS device trying to use and enroll in our BYOD portal/setup, they're getting: "Your browser is currently unsupported". 
I'm fairly confident it's any device that's upgraded to iOS 15, 15.1, 15.2. It was working on several older test iPhones last week. 
I have: 

Version: 2.4.0.357
Installed Patches: 5,8,9,14

Any thoughts on how to get this running again?

[franklinb]

I'm seeing the same result - sometimes, however it's a very long timeout and not really a suitable work-around to provide to customers.

[franklinb]

3.1p4 and 3.1p5 both with same issue.