A computer-implemented method, comprising: receiving, from a sender user device, first message data designated for a plurality of recipient user devices, the sender user device and the plurality of recipient user devices defining a messaging group; receiving connection information for the recipient user devices, the connection information having been generated by a connection server testing whether the recipient user devices are connected to the connection server, the connection information including verification signals describing the results of the connection tests such that the connection information describes whether network data connections that operatively couple the recipient user devices to a network are available; determining, by a processor, whether the network data connection to each of the recipient user devices is available based at least in part on the connection information; dispatching the first message data to those recipient user devices for which the network data connections are determined as available using the respective network data connections; dispatching the first message data to those recipient user devices for which the network data connections are determined as unavailable via one or more fallback data connections using one or more fallback messaging protocols and storing a fallback identifier mapping to the messaging group; receiving a reply to the first message data from a recipient user device to which the first message data was dispatched via a fallback data connection, the reply comprising second message data; parsing the fallback identifier from the received reply and identifying the messaging group at least in part from the parsed fallback identifier; and forwarding the second message data to the other user devices of the messaging group. receiving, from a sender user device, first message data designated for a plurality of recipient user devices, the sender user device and the plurality of recipient user devices defining a messaging group; receiving connection information for the recipient user devices, the connection information having been generated by a connection server testing whether the recipient user devices are connected to the connection server, the connection information including verification signals describing the results of the connection tests such that the connection information describes whether network data connections that operatively couple the recipient user devices to a network are available; determining, by a processor, whether the network data connection to each of the recipient user devices is available based at least in part on the connection information; dispatching the first message data to those recipient user devices for which the network data connections are determined as available using the respective network data connections; dispatching the first message data to those recipient user devices for which the network data connections are determined as unavailable via one or more fallback data connections using one or more fallback messaging protocols and storing a fallback identifier mapping to the messaging group; receiving a reply to the first message data from a recipient user device to which the first message data was dispatched via a fallback data connection, the reply comprising second message data; parsing the fallback identifier from the received reply and identifying the messaging group at least in part from the parsed fallback identifier; and forwarding the second message data to the other user devices of the messaging group.