Registration applies equally to SMS, MMS and RCS message aliases, as indicated by the CNMC. RCS messages are an evolution of SMS with advanced multimedia features. For practical purposes, the process is identical: when registering the alias, you simply need to select the message type: SMS/MMS or RCS. If you use both channels with the same alias, you can register it only once by indicating both message types. At Viafirma, we currently operate using SMS/MMS. If you have any questions about your configuration, please contact support.