Embodiments include methods performed by a V2X application enabler (VAE) client of a V2X User Equipment (UE) arranged for communication with a VAE server. Such methods include sending, to the VAE server, a registration or de-registration request to register or de-register for receiving intelligent transport system (ITS) messages. The registration or de-registration request includes an identifier of the V2X UE and an identifier of a first type of ITS messages from the VAE server, for which the V2X UE wishes to register or de-register for receiving. Such methods include receiving, from the VAE server a response indicating acknowledgement of the registration or de-registration request. Other embodiments include complementary methods performed by VAE servers, as well as UEs and application servers configured to perform such methods.