An apparatus of an OMA (Open Mobile Alliance) is provided in the invention. The apparatus comprises a CPNS (Converged Personal Network Service) server, a PNGW (Personal Network Gateway), and a PNE (Personal Network Element). The CPNS server is configured to transmit a device capabilities query request message which comprises a target ID (Identification). The PNGW is configured to relay the device capabilities query request message if the target ID does not indicate the PNGW. The PNE is configured to receive the device capabilities query request message through the PNGW and then to transmit a device capabilities query response message to the PNGW according to a PNE capability of the PNE if the target ID indicates the PNE. The PNGW is further configured to relay the device capabilities query response message to the CPNS server.