MVNOs Google Fi and Tello just unlocked this messaging upgrade for iPhones

Tello announced RCS support on iPhones via its Subreddit
Now, with iOS 18.4, that barrier is gone for users on Google Fi and Tello, both of which use T-Mobile’s network infrastructure. That means you no longer have to rely on third-party apps like WhatsApp or Signal just to send decent-looking photos or see when your Android friends are replying. To make sure this is active on your iPhone, you’ll need to go into your iPhone settings, update to the latest iOS, and then enable RCS manually under the Messages settings. And yes, the person on the other end will also need to have RCS turned on for everything to work smoothly.
This shift puts more pressure on other MVNOs to catch up, and it’s likely only a matter of time before more prepaid carriers enable support. Major networks like Verizon and AT&T already had RCS up and running, so the gap is closing fast.
It’s not perfect as end-to-end encryption between iPhone and Android still isn’t here, although coming soon. However, RCS on more carriers means we’re finally inching toward more consistent, modern messaging across platforms. If you’ve been using Google Fi or Tello on your iPhone and felt left out of the messaging upgrade party, this update is a pretty welcome ticket in.