Apple iOS 18 to support RCS: Here's what it is, how it differs from iMessage, SMS

During the WWDC24 keynote event on June 10, Apple announced that its Messages app will support RCS in iOS 18. Craig Federighi, Apple’s senior vice president of Software Engineering, confirmed this significant update while introducing new iPhone features that will be available when iOS 18 is released in the fall. Here we will explain what RCS is, why Apple is now supporting it and how it differs from SMS and iMessage. 

What is SMS? 

The Short Message Service (SMS) is a widely used messaging protocol that originated in the early days of mobile technology. In December 1992, Neil Papworth, an engineer at Vodafone, sent the first SMS text message, wishing his boss a "Merry Christmas." By the beginning of 2011, about 80 percent of all mobile phone users worldwide, estimated at 3.5 billion people, were sending SMS messages every month.

Despite its widespread use, SMS has limitations. Messages are restricted to 160 characters, and multimedia such as photos, videos, audio, and GIFs cannot be included. To address this, Multimedia Messaging Service (MMS) was introduced, but it also has size limitations. Furthermore, SMS lacks end-to-end encryption.

However, despite these limitations, SMS has an advantage: it operates through the mobile carrier's network, so it does not require a data plan. As a result, SMS has often been used as a fallback for more advanced protocols, including Apple's iMessage, even in today's era dominated by instant messaging platforms.

What is RCS? 

RCS, short for Rich Communication Services and also known as “Advanced Messaging,” is positioned as the next-generation replacement for SMS and MMS. It offers many features previously exclusive to over-the-top messaging platforms like WhatsApp.

The RCS Universal Profile includes support for read receipts, typing indicators, group chats, and the ability to send high-resolution images, videos, and audio clips. Google's implementation of RCS also includes end-to-end encryption (E2EE) for both one-on-one and group chats.

RCS messages are sent over a mobile data connection or Wi-Fi link, with SMS serving as a fallback. Despite this, SMS is likely to remain in use for the foreseeable future.

RCS is not intended to replace or compete with instant messaging apps. Instead, it is a communication protocol between mobile carriers and between phones and carriers. Using RCS does not require signing up for a new service. As long as your phone and carrier support RCS, and you’re using a compatible app like Messages by Google, you can benefit from all that the protocol has to offer, provided the person or people you’re messaging also meet these requirements.

How did RCS start? 

RCS work began before Apple announced iMessage. RCS is a multi-stakeholder project involving the GSMA, a trade body representing the mobile communications industry. In 2015, Google acquired Jibe Mobile and took a more active role in RCS proliferation. However, the early days of RCS were marked by false starts, with some carriers forming a short-lived joint venture to push the protocol forward before eventually aligning with Google. Even Samsung initially did its own thing before agreeing to make Messages by Google its default messaging app in the US.

What is iMessage? 

In June 2011, Apple announced iMessage just a few months before Steve Jobs passed away later that year. Unlike RCS, iMessage is a proprietary messaging protocol exclusively controlled by Apple and available only on iPhone, iPad, Apple Watch, and Mac devices.

Why is Apple now supporting RCS?

RCS and iMessage cannot communicate with each other. Therefore, when Android users try to send texts and media files to someone with an iPhone, Apple's Messages app defaults to SMS/MMS, leading to pixelated media files, the absence of read receipts and typing indicators, and the inability to include both iPhone and Android users in a group chat.

Apple had little reason to adopt RCS, as it felt no need to support a struggling competitor and did not hear much demand from its users. However, in 2022, the European Union passed the Digital Markets and Services Act, requiring "gatekeepers" like Apple to not favour their own systems or limit third-party interoperability. 

Despite the EU ruling that Apple's Messages app did not constitute a monopoly, Apple pledged to adopt RCS support months earlier. It is now confirmed that Apple will introduce RCS support with iOS 18 as part of its compliance efforts and possibly to placate regulators in China.

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