Section: 4.25 Support of MUSIM features
Content: A network and a MUSIM UE may support one or more of the MUSIM features (i.e. the N1 NAS signalling connection release, the paging indication for voice services, the reject paging request, the paging restriction and the paging timing collision control). If MUSIM UE supports one or more MUSIM features, the UE indicates support of one or more MUSIM features (except for the paging timing collision control) during the registration procedure. If the UE has indicated support of the N1 NAS signalling connection release or the reject paging request or both and the UE supports the paging restriction, the UE indicates support of the paging restriction. If the UE indicates support of one or more MUSIM features and the network decides to accept one or more MUSIM features, the network indicates the support of one or more MUSIM features during the registration procedure. The network only indicates the support of the paging restriction together with the support of either N1 NAS signalling connection release or the reject paging request. The network does not indicate support for any MUSIM feature to the UE during the registration for emergency services. If the UE is not currently registered for emergency service and the UE receives the CONFIGURATION UPDATE COMMAND message with the 5GS registration result IE value set to "Registered for emergency services", then UE shall behave as if the network did not indicate support for any MUSIM feature in the last registration procedure. If the network has sent CONFIGURATION UPDATE COMMAND message with the 5GS registration result IE value set to "Registered for emergency services", then network shall behave as if it did not indicate support for any MUSIM feature in the last registration procedure. If a UE stops fulfilling the condition to be considered a MUSIM UE as defined in subclause 3.1, and the UE has negotiated support of one or more MUSIM features, then the UE shall initiate a registration procedure for mobility and periodic registration update to indicate that all the MUSIM features are not supported (except for the paging timing collision control) as specified in subclause 5.5.1.3. A MUSIM UE operating in NB-N1 mode or in WB-N1 mode CE mode B does not indicate the support for paging indication for voice services during the registration procedure towards the network.