Their infrastructure is iMessage protocol specific, though, and that's incompatible with whatever Google does for RCS. So either somebody has to build some new

Their infrastructure is iMessage protocol specific, though, and that's incompatible with whatever Google does for RCS. So either somebody has to build some new service bridging the gap, or RCS encryption is "serverless" in the way that e.g. OTR was, but unlike Signal (which needs explicit server support for managing pre-keys to bootstrap new connections while the recipient is offline, for example).