Apple has announced that it will add support for end-to-end encryption to RCS messaging on iOS, although there are few details about when this will happen.

RCS support will be extended to include end-to-end encryption
After years of bizarre pressure over how Messages has blue bubbles for iOS users and green for Android ones, and maybe a nudge from China, Apple finally added support for RCS messaging with iOS 18. Its implementation, though, did not support Google’s implementation of end-to-end encryption.
Now as first spotted by 9to5mac, the RCS standards body GSM Assocation (GSMA) and Apple have announced new end-to-end encryption support on iOS.