A method for determining a capability of a user equipment. The user equipment is served by a non-shared network in a first place. The non-shared network is configured to transmit a message to the user equipment, the message including information on at least two PLMN identities. The user equipment is configured to deliver a response message from which it is determined if the response message includes information field reserved for at least one PLMN identity in the transmitted message. On a basis of an existence of the information field in the response message it can be determined that the user equipment supports network sharing. In other case it is determined that the user equipment is not supporting network sharing. A network node and a system implementing at least part of the method are also described.