A method in a mobility management node for delivering data to a wireless communication device, WCD, served by the mobility management node, operating in a communication network (10b, 10c) comprising a network entity, NE, (108, 110, 210, 240) and a radio access network, RAN, node serving the WCD, the method comprises: - obtaining (306, 402, 610, 710) by the mobility management node capability information indicating whether the RAN node supports acknowledgement of a successful delivery of data to the WCD; - receiving (207, 311, 409, 620, 720) by the mobility management node a data message sent by the NE comprising user data intended for the WCD; - sending (313, 411, 630, 730) by the mobility management node a control plane message comprising the user data to the RAN node for further delivery to the WCD; - sending (209, 650, 740) by the mobility management node a response to the NE: a) indicating an unsuccessful delivery of the user data to the WCD when a report is received (313, 411, 640) from the RAN node indicating that the user data was not successfully delivered to the WCD; otherwise; b) indicating an acknowledgeed delivery of the user data to the WCD when the RAN node supports said acknowledgement and an acknowledgement is received (313, 411, 640) from the RAN node indicating that the user data was successfully delivered to the WCD; c) indicating an unacknowledged delivery of user data to the WCD when the RAN node does not support said acknowledgement. - obtaining (306, 402, 610, 710) by the mobility management node capability information indicating whether the RAN node supports acknowledgement of a successful delivery of data to the WCD; - receiving (207, 311, 409, 620, 720) by the mobility management node a data message sent by the NE comprising user data intended for the WCD; - sending (313, 411, 630, 730) by the mobility management node a control plane message comprising the user data to the RAN node for further delivery to the WCD; - sending (209, 650, 740) by the mobility management node a response to the NE: a) indicating an unsuccessful delivery of the user data to the WCD when a report is received (313, 411, 640) from the RAN node indicating that the user data was not successfully delivered to the WCD; otherwise; b) indicating an acknowledgeed delivery of the user data to the WCD when the RAN node supports said acknowledgement and an acknowledgement is received (313, 411, 640) from the RAN node indicating that the user data was successfully delivered to the WCD; c) indicating an unacknowledged delivery of user data to the WCD when the RAN node does not support said acknowledgement. a) indicating an unsuccessful delivery of the user data to the WCD when a report is received (313, 411, 640) from the RAN node indicating that the user data was not successfully delivered to the WCD; otherwise; b) indicating an acknowledgeed delivery of the user data to the WCD when the RAN node supports said acknowledgement and an acknowledgement is received (313, 411, 640) from the RAN node indicating that the user data was successfully delivered to the WCD; c) indicating an unacknowledged delivery of user data to the WCD when the RAN node does not support said acknowledgement.