UPDATE 7/2/15:
We have completed our general ForeFlight Mobile compatibility testing of the public version of Apple iOS 8.4. We recommend caution when it comes to any iOS update, however our testing did not reveal any significant issues.
###
We are happy to report that the GPS accessory compatibility issue that resulted from the Apple iOS 8.3 update is resolved with the iOS 8.4 update released this morning. We have performed a quality review of the Bad Elf GPS Pro, Bad Elf GPS Pro+, Dual XGPS150, and Dual XGPS160 on a Wi-Fi iPad running iOS 8.4 and these devices perform as expected. Stratus 1 and Stratus 2 devices were not affected by this issue. We have also started our general ForeFlight Mobile compatibility testing of the final version of iOS 8.4.
Customers that wish to resume use of their affected GPS accessories can upgrade to iOS 8.4. Customers that do not need immediate access to the affected GPS accessories can opt to wait until ForeFlight completes its compatibility testing of the final iOS 8.4 release and issues an ‘all clear’ notice.
For your reference, here are the instructions on how to update the iOS software on your iPhone, iPad, and iPod touch.