However, even when RCS officially rolled out on iPhones with iOS 18, there were limitations. For one, RCS' biggest perk, end-to-end encrypted messaging, didn't work (and still doesn't work), which means texting between iPhones and Androids on RCS is as insecure as it is over SMS. What's more, you might not even get the other perks of RCS on your iPhone, since the protocol is carrier-dependent. At launch, only the major carriers—AT&T, Verizon, and T-Mobile—supported RCS. If you used another, you were out of luck.
9to5Mac spotted the latest updates to Apple's list of carriers that support RCS. As of Monday, Dec. 23, these are those carriers:
Boost Mobile (iOS 18.2 required)
Consumer Cellular
FirstNet
Metro by T-Mobile
Red Pocket
T-Mobile
US Cellular
Visible
As 9to5Mac highlights, the two major exceptions right now are Mint Mobile and Ultra Mobile. Combined, these carriers have about three million customers, and were acquired by T-Mobile earlier this year, so it's a bit surprising it's taking so long for them to adopt this messaging protocol. In all likelihood, these carriers will add RCS support in the near future.
Apps > Messages > RCS Messaging. Note that even if this setting is enabled, and your carrier supports RCS, you might not see RCS appear for all chats with Android devices. The Android device also must support RCS, including both the device, its carrier, and the messaging app in question. If the other user doesn't have RCS enabled for any reason, you'll see that SMS is the protocol used for that particular conversation.
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