When RCS messaging became available on the iPhone with the rollout of iOS 18, the technical director of the GSM Association teased that the next major milestone for the messaging standard is the addition of interoperable end-to-end encryption.

With the GSMA releasing new RCS specs, Apple pledges to 'add support for end-to-end encrypted RCS messages to iOS, iPadOS, macOS, and watchOS in future software updates.'

Ironically, a major uncertainty is E2EE itself. This is now being probed by the UK government, which has decided to use Apple as its test case in a campaign to introduce backdoors into the encryption used in iCloud services. So far, Apple is resisting, choosing to disable security rather than allow surveillance. Talks are reportedly ongoing.