I assume in Germany any of the hundreds(?) of providers that use the O2 (Telefónica) network should work, if even my 14 years old free Internet Netzclub card does. It was taken over by FONIC recently, I added that one to the list.
The switch was there and worked to turn on from the beginning with the first beta that introduced RCS.
I recently received my first RCS with a confirmation code from Klarna (payment service). Maybe there were others before and I didn't notice it. It even came with some more information and a profile image.
My SE3 screen is a little too small to show everything. "Report Junk" and "Block Sender" is at the bottom. In SMS confirmation codes from other websites, I don't even see a number and there is only the "Hide Alerts" slider in the info screen.
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