I know I know, beta releases and all, but this is a new one. In my years of Xcode and OS X betas, I've never seen where a stable release of Xcode was not compatibility with an OS X beta. This is obviously a huge problem for many people; folks need 10.11 for beta testing/development, but many of us do not have two machines in order to have to OSs at once.
Unlikely, but if I could get an official response it would be amazing - if I am submitting apps using Xcode 6.3 and 6.4 before the fall, am I going to need to revert my machine back to OS X 10.10, or will a subsequent beta fix the incompatibility?