T-Mobile today announced that it's improving texting with "advanced messaging," which adds read receipts, real-time chat, and large file support to SMS through a standard called Rich Communication Services.

In other words, it makes texting a lot more like Facebook Messenger, WhatsApp, Google Hangouts, or your favorite third-party messaging service.

According to a blog post from T-Mobile CTO Neville Ray, Advanced Messaging will work by default, won't require any downloads or third-party apps, and will interoperate with other global carriers using the RCS "joyn" standard. It's starting on the new Samsung Galaxy Grand Prime phone, but will come to the Galaxy S5 and S6 through a software update. "Nearly a dozen more hot devices will come with Advanced Messaging this year alone, and, in the future, we expect it will be a standard feature on new smartphones sold," the post says.

If you combine SMS text messaging and MMS picture messaging, carrier-controlled messaging has declined slightly from its peak in 2012, according to CTIA, the wireless industry trade group. Meanwhile, third-party messaging apps such as Facebook, WhatsApp, Kik, Snapchat, Viber, and Apple's iMessage, known as "over the top" or OTT messaging apps, have been booming. These apps typically offer richer and more colorful experiences, but they're closed ecosystems out of the carriers' control.

RCS is the carrier-run alternative. It's often linked with voice-over-LTE (VoLTE), but doesn't require it. The global carrier consortium known as the GSMA has been pushing RCS under the "joyn" brand since 2012, but it's gotten very little uptake. MetroPCS, now part of T-Mobile, launched RCS with fanfare in 2012, but then didn't do much with it. It forced users to download a third-party client from Google Play, which few did. Sprint also half-heartedly offered an RCS-compatible downloadable third-party client in 2013, at which point wireless analyst Dean Bubley termed RCS "an undead Zombie technology ... we've still got a few lonely operators kicking over its rotting corpse at the moment."

The GSMA claims 41 operators in 32 countries are running RCS, but that number is immediately in question because it includes Sprint's "messaging plus" app that few people downloaded, which Sprint hasn't discussed in years. The Google Play entry for the Messaging Plus app, which appears to be globally available across all carriers, shows it has fewer than 5 million downloads. Sprint alone has approximately 57 million customers, almost all of whom use text messaging.

T-Mobile's RCS will be quite different, because it will be the default. It'll be the first carrier in the U.S. to replace the standard Android messaging app with an RCS-compatible implementation.

"It's not an app at all.  It's built right in, just like SMS or MMS are. Preloading an over-the-top messaging app and calling it RCS is easy.  The hard part is making it work across all networks and devices," a T-Mobile spokeswoman said.

There we get to the so far unrealized promise of RCS. SMS is still used because it's everywhere; you don't have to wonder about what carrier or what type of phone your friend is using. RCS on T-Mobile will be the most-used implementation yet, because it'll be the default. But it'll only be able to face down its OTT rivals if T-Mobile can get all the other carriers on board.

We'll have a review of the new T-Mobile RCS phones and messaging suite soon.