When Apple announced last year that it would finally bring RCS support to the iPhone, it seemed like the beginning of a new era in tech and communications. Finally, Androids and iPhones could message directly with one another without having to go through SMS, an inherently insecure and outdated messaging protocol responsible for poorly functioning group chats, low-quality images and videos, and most things we associate with "green bubble" messaging. 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 carriersAT&T, Verizon, and T-Mobilesupported RCS. If you used another, you were out of luck. Since then, things have changed. More and more carriers have adopted the protocol for iOS, so chances are pretty high your iPhone can message other Android users over RCS.9to5Mac spotted the latest updates to Apple's list of carriers that support RCS. As of Monday, Dec. 23, these are those carriers:AT&TBoost Mobile (iOS 18.2 required)C SpireConsumer CellularCricketFirstNetH20 WirelessMetro by T-MobilePureTalkRed PocketSpectrum MobileT-MobileTracFone / Straight TalkUS CellularVerizonVisibleXfinity MobileAs 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.As a reminder, you can make sure RCS is enabled on your iPhone from Settings > 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.