I'm having the same problem as someone on the ESRI forums linked here:
https://geonet.esri.com/thread/165647
Namely....
I was building a new deployment for an iPad and through the Apple developer site it requested I accept a new license agreement today. When I downloaded a new provisioning profile it updated Xcode and now the build kits for iOS are invalid in QT Creator.
I can build it just fine in Xcode and deploy to the device it's just the build kits are gone in creator.
Any thoughts?