This is a great question, probably one a lot of developers have. I’m going to take this opportunity to make an official statement on Bitcode, and publish this post as a FAQ.
Once Bitcode has been added to a library it is a requirement that developers use Xcode 7, Xcode 6 will not understand the Bitcode binary and will fail if attempted to link. While Apple permits the submission of applications to the store using Xcode 6 and does not require Bitcode we intend to leave the current stable FMOD Ex 4.44.xx branch without Bitcode support. This will ensure maximum compatibility for existing developers.
As Bitcode seems to be the future of iOS we have enabled support for it in our latest FMOD Studio 1.07.xx release (1.06.xx will remain without Bitcode for compatibility).
We encourage all developers of new applications to move to FMOD Studio to receive the latest features and optimizations for all platforms. FMOD Ex is a legacy product, while still maintained for bug fixes it will not receive non-essential functionality.
As of the date of this post it is not a requirement to submit to the app store with Bitcode enabled. Disabling Bitcode for your project will not affect your title in any way. If it becomes a requirement we will update the FMOD Ex release to include it.