Forget iOS 18—Millions Of iPhone Users Now Have RCS Messaging

In amongst all the excitement about what Apple will or won’t announce on AI at WWDC, the other major iOS 18 change will be its biggest ever update to iMessage—the introduction of RCS. But there’s a major security issue that’s not being fixed.

RCS is the advancement on SMS that’s now the default protocol on Google Messages—Android’s iMessage equivalent. That’s won’t be the case on iPhone, and instead we expect RCS to run in parallel. Put simply, green bubbles will remain green, albeit they’ll be RCS and not just SMS, which means the functionality will improve.

ForbesWhatsApp’s Biggest iPhone Update For 2024 Is Here-Its Worst In YearsBy Zak Doffman

But while RCS is end-to-end encrypted on Android, it won’t be on iPhone. Google’s encryption layer is a proprietary add-on, and there’s been no talk yet of Apple and Google collaborating to bridge iMessage to Google Messages encryption. Unless and until that changes, don’t switch your secured apps to this new cross-platform fudge.

Surprisingly, it turns out this won’t be the first time RCS has been on iPhone—it has been there for years. As unearthed by Android Authority, “while the vast majority of iPhone users will get their first taste of RCS messaging with the upcoming iOS 18 update, millions have already been (unknowingly) enjoying its capabilities.”

This isn’t iMessage, but Japan’s +Message app. As lauded at the time by RCS standard-setter, GSMA, “Japanese operators KDDI, NTT DOCOMO and SoftBank launched +Message using the GSMA’s RCS standards in May 2018, providing full interoperability and a common user experience for next-generation messaging.”

But despite this carrier backing, +Message has not really dented Line’s market lead in Japan, even with the 32 million users they reported by the end of 2022. Line has retained its top spot, with around three-times the user base. And, unsurprisingly these days, Line messages are fully end-to-end encrypted, with its “Letter Sealing.”

The company behind +Message’s back-end has been bullish on its position in Japan, describing +Message as “a single app that’s downloadable for all three of the operators that we support there and we enjoy consumers utilizing the RCS service there both on Android and iOS operating systems.”

But it seems that carrier support for +Message might now start to shift towards Google Messages, in which case it will fall under the part-integration Apple is adding to iMessage, rather than a separate app that needs to be installed.

ForbesSamsung Issues Critical Update For Millions Of Galaxy UsersBy Zak Doffman

From a user perspective, though, there’s no reason to think this will make any larger a dent in Line’s user base in Japan. The challenge for Apple and Google is that the over-the-top messengers, such as Line and more obviously WhatsApp, are fully secured, seamless cross-platform, and thriving as regards user numbers.

It’s high time SMS on iMessage was replaced with a better alternative, and RCS is certainly that, but it doesn’t mean the update will push people to ditch their current, more secure go-to daily platforms.