With iOS 26.4, iPadOS 26.4, and macOS Tahoe 26.4, Apple is testing end-to-end encryption (E2EE) for RCS messages, a security feature that is not currently available for cross-platform messaging
Messages sent by RCS that have end-to-end encryption will feature a lock icon in the conversation interface. As of right now, Apple is testing iPhone-to-iPhone RCS encryption, with the feature set to roll out for iPhone and Android conversations in a future iOS 26 update.
Messages that feature E2EE will feature a lock icon in the conversation UI, both for iMessages and RCS Messages.
