irrenarzt
Compat mode didn't make a difference on my end either. I also had wifi disabled the entire time, and my RCS stayed connected for about 3.5 days. I had gotten so hopeful when I saw that I had made it past the 72 hr mark, but by that evening it had disconnected. I want to keep troubleshooting this because, especially with Apple on board and google Messages being the stock messaging app on all droids, I do think RCS is the future.
Note to others: I also tried installing Carrier Services, and that didn't seem to make a difference. And there had been some talk earlier in this thread about sniffing the traffic to see if Google was phoning home with a bunch of telemetry; well, once I got RCS connected I did start logging my traffic, and I was happy to see that the only URLs it connected to were m.talk.google.com and my carrier's PCSCF url. In other words, I don't think it was sending more than the bare minimum data required to maintain the connection.