Apple is apparently working on getting encryption added to the standard
In a background briefing with reporters, Apple spokespeople touted the company's recent announcement that it will support the RCS messaging standard for iMessage sometime during 2024. In order to attend Apple's briefing and view a background document, we had to agree to paraphrase the company's remarks instead of quoting them directly.
Apple clarified that it is not implementing RCS as it exists today because it doesn't believe the standard offers enough privacy and security. Apple said it is working with a standards body—this is likely a reference to the GSMA—to ensure that the version of RCS it eventually implements will support encryption and strong privacy and security.
Apple said that once it adopts RCS, iPhone and non-iPhone users will be able to exchange messages with higher-resolution photos and videos, and will experience improved group texting. Apple said it hasn't brought its own message app to non-Apple devices because the user experience wouldn't meet the company's standards and that it cannot ensure that a third-party device's encryption and authentication are secure enough.