Apple Expands RCS Encryption and Memory Protections in iOS 26.4

Apple's iOS/iPadOS 26.4 developer beta introduces end-to-end encryption for RCS messaging between compatible Apple devices, expanded Memory Integrity Enforcement protections allowing apps to opt into full MIE, and Stolen Device Protection expected to be enabled by default; the SDK is included in Xcode 26.4 with additional developer fixes and notes. These notes describe security and privacy feature updates and rollout status rather than a cybersecurity incident or compromise.