
RCS, or Rich Communication Services, will bring several features to iOS 18 that enhance messaging between Apple and Android devices. These features include:
Read receipts: Users will be able to see when their messages have been read by the recipient, regardless of whether they're using an iPhone or an Android device4.
Typing indicators: Users will be able to see when the person they're messaging is typing a response, similar to the "..." indicator in iMessage.
High-quality media sharing: RCS allows for the sending of high-quality images and videos. This means that users will no longer have to deal with reduced image and video quality when sending multimedia messages between iPhone and Android devices.
Support for larger files: RCS supports larger file sizes compared to the current SMS/MMS protocol. This means that users can send larger files without any issues.
Real-time chat: RCS messages can be sent over Wi-Fi or cellular data, which means that messages can be sent and received in real-time, similar to iMessage.
Group chats: RCS will improve the functionality of group chats between iPhone and Android users, with features like read receipts and typing indicators working across both platforms4.
Better security: RCS messages are more secure than SMS/MMS messages, although they may not be end-to-end encrypted like iMessage conversations.
These features will significantly improve the messaging experience between Apple and Android devices, making it more seamless and user-friendly.

RCS messages will be visually differentiated from iMessage texts on Apple devices through the use of different colored bubbles. iMessage texts will continue to appear in blue bubbles for iPhone-to-iPhone communication, while RCS messages will appear in green bubbles, similar to the current SMS and MMS messages6. This distinction allows users to easily identify the type of message they are receiving, whether it's an iMessage or an RCS message.

Apple's decision to implement RCS in iOS was influenced by a combination of factors, including increasing regulatory pressures and the need for better interoperability between different platforms. The European Union, for example, required Apple to open iMessage to other platforms, which accelerated Apple's decision to adopt RCS. Additionally, adopting a universal messaging standard like RCS demonstrates Apple's willingness to support device interoperability and address concerns raised by regulators in several countries.