A change Apple is making to improve privacy in an upcoming version of its iPhone operating system has alarmed an unlikely group of software makers: developers of privacy-focused encrypted messaging apps. They warn the change, which is already available in public test versions of iOS 13, could end up undermining the privacy goals that prompted it in the first place.

The Information previously reported that the technical change Apple is making to its next operating systems, iOS 13, has sparked concern at Facebook, which believes it will have to make significant modifications to encrypted messaging apps like Facebook Messenger and WhatsApp to comply. But a much wider group of developers of encrypted messaging apps—including Signal, Wickr, Threema and Wire—is scrambling to overhaul their software so that key privacy features continue to work. 

Apple told The Information on Wednesday in a statement that it is working with the developers to resolve their concerns. “We’ve heard feedback on the API changes introduced in iOS 13 to further protect user privacy and are working closely with iOS developers to help them implement their feature requests,” an Apple spokerson said, using the abbreviation for application programming interfaces, a tool that lets developers take advantage of basic functions in operating systems.