In one implementation, a computer-implemented method includes: receiving, at a computer system, a multimedia message service (MMS) message for delivery to a client computing device; storing, by the computer system, the MMS message; generating, by the computer system, a traditional short message service (SMS) message including a notification that the MMS message is available for download from the computer system; transmitting, by the computer system, the SMS message to the client computing device; receiving, after transmitting the SMS message, a request from the client computing device to download the MMS message; and sending, by the computer system, the MMS message to the client computing device.