It's that time of year again, folks. As the tech world has sights set on the latest Apple event that is producing the new iPhone 16 as we speak, we all know we'll be seeing slightly improved phones, some impressive specs, and a few 'innovative" or "magic" new features from Apple. For me, however, the...
The standard is fine: https://www.gsma.com/newsroom/wp-content/uploads/RCC.71-v2.6-1.pdf
This isn’t an Apple standard or a Google standard, it’s a telecoms standard. It’s made for everything from IoT to flip phones to tablets to smart cars.
Nobody has bothered to build an app for it, though. Well, carriers have, but nobody uses their carrier’s messaging app.
RCS is an open standard, but Google’s implementation of it isn’t AFAIK. That’s why there exist no 3rd party RCS client outside of those praised by Google.
Google’s implementation is just a bunch of weird text sent over texts. It’s using the standard as a transport for their own extensions.
That doesn’t mean other apps can’t communicate with Google’s client. You can’t use Google’s special sauce like encryption (without reverse engineering the details) but you could very well use your own.
What developers want when they say they want Google to open RCS is for Google to take the RCS code out of their messages app and put it into a standard API, the way SMS and MMS work, so developers don’t need to go through the trouble of implementing RCS and basically be able to use the existing code without changes. That’s a nice idea, but I don’t think it’ll happen any day soon. Google generally doesn’t contribute their closed source stuff back into open source Android. There is one type of RCS authentication that requires interacting with the SIM card, which only privileged (system) apps can do. All other forms of authentication can be implemented by any app. With multiple SIMs, you could even use different apps for different services. However, they’d need to actually implement the RCS spec, which everyone is hoping to avoid.
iPhones will be able to message Android phones without Google lifting a finger. Flipphones will be able to do it too. Things like video calling, sending money, and stickers can all work, because that stuff works over standard RCS. The lack of encryption is a pain (though I doubt it’d take long for someone to reverse that) but it’s not something existing cross platform texting solutions offer.
Google Messages is the Microsoft Wordpad of text editing. Pieces of it are open, most of it is composed of public APIs, and it’s no more than a very specific implementation of existing standards.
Are those carrier apps FOSS? Are they on F-Droid? How do you install them? If not, it’s not really any better.
Just because no open source developers have bothered to implement a standard doesn’t mean the standard is closed. Anyone with interest could set up an RCS server, connect an RCS app (by manually specifying the base URL or by hosting a private 4G network) and start hosting their own RCS infrastructure, though you’d probably face difficulty trying to connect your open source network to the big ISPs.
OpenIMSS is working towards a fully open source LTE (and up) network that also sports RCS support. The voice/video calling features are already supported by opensips. I believe OpenIMSS and the underlying base software is run through docker. It’s a rather niche piece of software, as you have to be an MVNO or a carrier to connect to the public RCS network. Nothing prevents the open source community from running their own network, though; that’s how Matrix and XMPP work, after all.
As for RCS clients, https://github.com/Hirohumi/RustyRcs seems to fit the bill, though I haven’t run it myself to see how complete it is. There’s no pre-built APK but if you have Android Studio and Rust on your machine you should be able to get it running in no time.