I too got the Garmin Glo update and everything works again. I had to wait a bit until my PC recognised the Glo, and found the driver, before installing the update. I also needed a couple of goes at getting the Bluetooth connection.

I use an iPad mini and Dual XGPS150E with Skydemon. I have been on the phone to Apple Support this afternoon. They tell me that is it a Skydemon and Dual issue as they should update their products to work with iOS 8.3.

It seems this issue should be fixed in iOS 8.4: Apple Seeds Second iOS 8.4 Beta With Revamped Music App to Developers and Public Beta Testers - Mac Rumors

I find it interesting that Apple should release a fix for something which is not a bug, and is supposedly the responsibility of app/hardware makers to resolve.

There's a video on how you can get iOS 8.4 beta on your iDevice, even if you're not an official beta tester. Haven't tested it myself but might be a temporary solution for some that can't wait until the official 8.4 release.

Garmin Glo Firmware upgrade
 

I wouldn't even know how to downgrade to an earlier version of iOS (after a newer version has been installed). Neither would I recommend to become a beta tester for iOS 8.4 on the same iPad that I rely on for my flight safety. Who knows what new problems I will encounter...

Although not widely published, the firmware upgrade of the external GPS receiver should fix the problem. I am using the Garmin Glo on a non-cellular iPad (that is, an iPad without inbuilt GPS receiver). The firmware upgrade works as advertised and described by Coger below, and fixed the problem for me.

This doesn't help users of older devices for which there isn't a firmware fix.

As things stand, for a large number of people, installing the iOS 8.4 beta is the only solution apart from buying a new GPS receiver.

I'm normally an enthusiastic supporter of Apple, but the way they have handled this issue has been shocking. Why on earth they couldn't provide a small 8.3.1 update to get everyone back up and running weeks ago is beyond me.

stevelup wrote: Yes, 100% agree with you. Apple won't release 8.4 until June 30th :ugh:

Can someone please confirm the method of installing the 8.4b works and brings back the Dual External GPS signal to the wifi-only iPad and thus makes Skydemon in flight navigation work again?

Can't check myself as the Dual happens to be on my airplane, which happens to be in another country...

Thanks in advance!

The 8.4 beta definitely resolves the issue. I have helped several people install it successfully.

Thanks stevelup, installed!