iOS 26.4 beta adds support for testing end-to-end encrypted RCS messaging

Apple added RCS support to iPhone with iOS 18.1, enabling richer cross-platform messaging between iPhone and Android users. This ...

iOS 26.4 Beta Tests A Major Android Integration (That Won't Arrive Anytime Soon)

iOS 26.4 is going to be a pretty big update for the iPhone. It's expected to launch late in March based on past x.4 releases ...
Macworld

iOS 26.3.1 update in testing as new Apple releases loom

Macworld reports that Apple is testing iOS 26.3.1 without a beta cycle, with the update expected within one to two weeks.

RCS encryption surfaces in iOS 26.4 developer beta, but testing is extremely limited

Apple has taken a small step toward securing cross-platform messaging, with early RCS encryption support now appearing in the iOS 26.4 beta. Just don't expect to get that much testing done right now.