Five days ago, about ninety minutes into the WWDC 2024 keynote, Craig Federighi mentioned — almost in passing — that iOS 18 would support RCS messaging. He spent roughly thirty seconds on it, giving it no demo, no deep dive, no explanation of why it mattered. Just a brief note that Apple would adopt the GSMA Universal Profile for rich messaging with Android users.

I waited for this announcement for years. Literally years. I worked on the RCS ecosystem at Google, where I saw firsthand how the protocol developed and why adoption mattered. I’ve written about the protocol, built tools for it, argued with skeptics about it. And when the moment finally came, Apple treated it like a footnote.

Classic Apple. And honestly, fine. What matters: the decision, not the presentation.

What Apple actually announced #

iOS 18 includes RCS support based on the GSMA Universal Profile. Person-to-person messaging only at launch — no RCS Business Messaging (A2P) for brands sending to iPhone users. The features coming to cross-platform conversations:

• High-resolution photo and video sharing — replacing the compressed, grainy MMS experience that somehow persisted into the 2020s
• Read receipts and typing indicators across platforms
• Better group chat support (naming groups, adding/removing participants)
• Wi-Fi messaging as a fallback when cellular drops out

RCS replaces SMS/MMS as the fallback protocol when iMessage falls back, covering the iPhone-to-Android case that previously forced people onto 1992-era text messaging. That means: iPhone to iPhone stays on iMessage (blue bubbles). iPhone to Android now uses RCS instead of SMS.

The green bubble stays. Apple keeps the visual distinction between iMessage and RCS conversations deliberately. The experience inside those green-bubble chats improves dramatically; Apple just isn’t pretending RCS equals iMessage.

Why this took so long #

Apple resisted RCS for years. Google ran a public campaign — the “Get The Message” initiative — pressuring Apple to adopt the standard. Apple’s response: “use iMessage” (and, implicitly, “buy an iPhone”).

The technical arguments for resistance were weak. Apple’s real resistance ran strategic: iMessage lock-in ranks among the strongest competitive moats in consumer technology. Green bubbles being terrible served as a feature, not a bug — it made Android users look bad in group chats and gave teenagers a reason to pressure their parents for iPhones.

So what changed? A few things, probably. Regulatory pressure in the EU (the Digital Markets Act has interoperability provisions that could target iMessage). Growing carrier frustration — AT&T, T-Mobile, and Verizon all moved to Google’s Jibe platform for RCS by early 2024; they weren’t happy about Apple holding back the ecosystem. And sheer market reality: RCS device coverage on Android crossed the tipping point where Apple’s refusal started looking less like strategy and more like pettiness.

Credit where earned: Apple made the right call. Late, but right.

What this means for the messaging ecosystem #

The numbers tell the story. Juniper Research projected 1.1 billion active RCS users in 2024 — and that before Apple’s announcement. Once iOS 18 adoption ramps up (typically 70-80% of iPhones within a year of release), the addressable RCS base effectively doubles.

For years, the biggest problem with RCS: the Apple-shaped hole in the ecosystem. Android to Android messaging over RCS worked well. iPhone to iPhone over iMessage worked beautifully. But the cross-platform experience — which accounts for a huge portion of daily messaging volume, especially in the US — sat stuck on SMS from 1992.

That hole now gets filled. Not perfectly (more on that in a moment), but filled.

For carriers, this brings vindication. They bet on RCS as the SMS successor and spent years upgrading their networks to support it. All three major US carriers moved to Google Jibe in the past year, signaling they went all-in regardless of Apple. Now they have both platforms.

For consumers, the change comes down to this: texting between iPhone and Android gets dramatically better. No more photos looking like someone shot them on a potato. Group chats actually work. Read receipts cross the divide. It’s the experience everyone assumed texting already had.

What’s missing (and when it lands) #

The announcement marks a starting point, not a finish line. A few things stand out as absent.

End-to-end encryption for cross-platform conversations. The big one. iMessage conversations carry end-to-end encryption. RCS conversations between Android users on Google Messages carry end-to-end encryption. But cross-platform RCS (iPhone to Android) ships without encryption at launch. The GSMA develops Universal Profile 3.0 with encryption based on the MLS protocol; that spec hasn’t finalized yet.

Apple addressed this directly in the announcement: they called out the cross-platform E2EE gap explicitly. I read that as both transparency and a hedge — Apple can point to the GSMA timeline rather than taking responsibility for the delay.

RCS Business Messaging on iOS. The WWDC announcement covers P2P only. Brands sending RCS messages to consumers don’t reach iPhone users at launch. A significant limitation for the business messaging ecosystem — the iPhone gap persists for A2P use cases even after iOS 18 ships.

Full feature parity. iMessage has features RCS lacks: reactions with specific emoji, edit and unsend functionality, SharePlay, shared albums. Cross-platform conversations via RCS end up better than SMS; they don’t match the iMessage-to-iMessage experience. Apple has no incentive to close that gap completely.

The green bubble politics #

Apple keeping green bubbles for RCS conversations reflects a deliberate choice, not a technical limitation. They could render RCS messages in the same blue-bubble style as iMessage. They chose otherwise.

Two minds about this. On one hand: petty brand differentiation that perpetuates the social stigma around Android users in group chats. On the other hand, the distinction communicates something real — iMessage conversations carry E2EE; RCS conversations (initially) don’t. The color difference tells users something meaningful about the security properties of their conversation.

My prediction: as cross-platform E2EE arrives via the GSMA’s Universal Profile 3.0, the argument for keeping the color distinction weakens. Apple may eventually unify the UI. Or they keep it forever because the marketing value runs too high. Genuinely no idea which.

What I’m watching next #

Three things determine whether this announcement fulfills its potential:

Adoption speed. iOS 18 needs critical mass before the ecosystem effects materialize. Apple’s track record on iOS adoption runs strong; enterprise-managed devices often lag by months.

GSMA’s encryption timeline. Cross-platform E2EE fills the missing piece that makes RCS a complete iMessage alternative. If Universal Profile 3.0 takes another two years, the window for competitors (WhatsApp, Signal) to cement their position as the “secure cross-platform” option widens considerably.

Business messaging support. P2P carries the consumer story. A2P (business-to-consumer) carries the revenue. Until RCS Business Messaging works on iOS, the commercial case for brands to invest in RCS stays half-built.

This marks a landmark moment for mobile messaging. Not because the technology is new — RCS existed for over a decade — but because the last holdout finally joined. The messaging experience between the world’s two dominant phone platforms gets meaningfully better for billions of people.

It just took Apple a few years longer than it should have.