Our friends at iZotope have announced El Capitan support for their audio software. They say on their website.
We’re happy to announce official support for Apple’s OS X 10.11 El Capitan. Thank you for your patience as we ensured a smooth-sailing product experience on the new operating system. After you follow the relevant instructions below for the products you own—and if all your software by other vendors is OS X 10.11 compatible!—you are safe to update your operating system.