Apple started to send messages to the Developers whose application can change after their review. The breached rule is the App Store Review Guideline 2.5.2 and seems to be related to all applications that use Rollout.
Brace yourself: Swift is coming
Swift was introduced at Apple's Worldwide Developer Conference (WWDC) 2014 as a replacement for Objective-C. It is the future and every Apple developer is waiting the right moment to start to use it: is this the right moment?