Google's Android version of iMessage is here. But there's a catch

People with Android phones in the United States will now be able to opt into the new texting service that Google calls Chat.

The Android version of iMessage is based on a wireless standard called Rich Communication Services (RCS), and is supposed to replace SMS texts.

"Texting is largely based on the SMS standard which lacks a lot of modern features, like sharing high quality photos and media or being able to message over Wi-Fi," said Sanaz Ahari, Google's product management director. "We just felt like we had to address that user need."

Chat, which started in the UK and France in June, is an easier way to text on Android. Like iMessage, it supports read receipts and ellipsis symbols to indicate when people are typing. Chat also lets people send texts through Wi-Fi, so they can save their cellular data. And it lets them send higher resolution images and videos.

Dan O'Connell, an analyst at research firm Gartner, said Google has long needed to catch up with Apple's iPhone and RCS is a way for it to do so.

"They had been hoping that the service providers would work on supporting RCS themselves," he said. "But that was very slow to happen, so I think that decided to take the initiative themselves."

Like iMessage, users can opt into the service or disable it if they don't want it. All Messages users in the United States will be able to chat with each other through RCS, as well as with Samsung Messages users on Sprint and US Cellular.

Routing RCS messages is more complicated than other messaging apps, but Google has made it simpler by providing RCS chat directly through its own servers instead of waiting for the carriers to offer them.

But the rollout may not be as seamless as Google hoped.

First, there's a privacy issue. Unlike iMessage, WhatsApp and Signal, RCS doesn't offer end-to-end encryption. Google can still technically see messages as they arrive on its servers and may have to turn them over to law enforcement if asked. This could be a concern for Android users and security advocates.

Then there is the fact that the networks of the big four US carriers -- Verizon, AT&T, Sprint and T-Mobile -- currently can't connect to each other via RCS. They recently announced that they will join forces next year, and Google said it is "willing to work with any carrier to connect their RCS users."

It's possible, however that the carriers' own texting apps could conflict with Google's Android Messages app, according to The Verge.

"Having Google servers interact with the carrier services' servers, and making sure that everything is fully synchronized, poses some degree of risk," said O'Connell, the Gartner analyst. That could be a problem "if Google makes an update and that doesn't get propagated to the carriers."

Google has tried different chat solutions in the past -- Allo, Hangouts, Duo and Android Messages. And despite its history of dysfunctional messaging, Android has dominated the market through its numerous partnerships with carriers and lower prices. In 2018, a staggering 74% of smartphones sold worldwide ran on Android, according to data from Gartner.