Could not they just replace the XMPP protocol with whatever better protocol, while keeping the GTalk alive.

They kinda did exactly that. GTalk became Hangouts which is no longer quite XMPP.

Well, not only did they change the protocol, they ruined the UI too.

It's kinda sad how they ruined a superb product and replaced with something some par!

X in XMPP stands for eXtensible. They could simply augment XMPP to match their needs better - and guess what, it's exactly what happened in last years. Now XMPP is a good, modern, battery- and UX-friendly IM protocol, with some clients even E2E encrypted by default.

I had Google Talk on my phone for ages, I'm not getting what you mean by this. I had no issues. It was fast, to the point, and worked.

What makes you say it's not a good mobile protocol? It had some problems in the early 2000s on mobile, but these days it has stream management similar to TCPs and XML compresses very well. As I mentioned in another comment, there are people running it over very low bandwidth HF radio, if it works well there it works well over phones, but I'd be curious to see why people still think otherwise. (Google Talk, naturally, never did implement any of the parts that make it good on mobile, just lilke they refused to do TLS on server to server connections, so note that I'm not arguing that Google Talk was good on mobile, just that if they'd worked on it a bit it could have been)

What service is using it at scale these days? I can't really think of a popular user. After a certain point it just becomes a headache.

When I was working with ejabberd clusters servicing mobile clients it worked but I've had a lot less pain just using a custom protocol over websockets. My personal experience also seems to be mirrored throughout the industry as all the big players eventually move away from xmpp.

Most ironically, Google is using it for their Cloud Messaging solution (https://developers.google.com/cloud-messaging/ccs and https://firebase.google.com/docs/cloud-messaging/server#choo... for the replacement) to allow applications to talk with a backend.. The advantages over HTTP are multiple: better battery life, bidirectional communication, asynchronicity.

Riot Games is also using it for the messaging part of League of Legends (https://engineering.riotgames.com/news/chat-service-architec...)

XMPP is also used by military organisations such as NATO (https://www.isode.com/solutions/military-xmpp.html)

The sad truth about XMPP is that it just works, but it has a very bad publicity because there's just no marketing around it, and it's never used directly by users. So it suffers from that wrong image that is just completely outdated.

You'll notice that the google links mention that the xmpp api is deprecated. I'm not sure what Riot uses these days but the xmpp connection is no longer available to third parties.

That sad truth is that people who actually use it end up dropping it. Its not some conspiracy. It just wasn't cutting it.

It's not XMPP that's deprecated, it's the whole CCS (first link) that's being replaced with Firebase (second link). The XMPP api is still present in the replacement.

While not fully consistent the XMPP api is referred to as legacy on much of FCM documentation. https://firebase.google.com/docs/cloud-messaging/server

You also misunderstand what this api is referring to. These are APIs for your server to connect to Google's. This is not a direct http and xmpp connection to mobile devices. That's all abstracted away from this.

All big players who have an interest in building a walled garden - yes, that sums up "all big players".

GTalk was awesome while it was federated.

I don't think lack of technical expertise to fix whatever needs to be fixed is what caused Google's demise in the messaging domain.

By "not a good" you mean an open protocol not controlled by Google?

No, by "not a good" he probably means that it's not well suited for low battery consumption expected from a mobile device.

Don't push your words on other people :(

The battery argument is just misinformed. The real reason Google dropped XMPP was not a technical one. Yes, Google claimed it was not "cloud ready" at that GoogleIO. The same one where they announced Google Cloud Messaging, based on, wait for it, XMPP.

IIRC WeChat started from the ground up with a custom protocol designed for compatibility/efficiency with low bandwidth mobile networks for maximum reach, IMHO a great example of thinking outside the box of "let's use XMPP since it works".

Just curious, who else is using that protocol?

Don't think anyone is, I thought there was a hacker news story on it but I could not find it with search, sorry.

Maybe it wasn't in 2006, but it wasn't that hard to make it a good mobile protocol and now it certainly is.