Don't rely on RCS!
Unfortunately, #RCS is worse than #SMS. (It used to be worse than #CVS, but that was something completely different.)
#FreeSoftware operating systems can easily support SMS and even #MMS, e.g. with #ModemManager. RCS is completely locked into #BigTech #duopoly Google + Apple and cannot be supported by #Mobian or free Android flavours.
Use #RFC6120 instead. Open, free, #standardised, federated #InstantMessaging for all!
#federation #digitalSovereignty #IETF #Jabber #XMPP