# Registration messages Registration messages: Reference IMSI DETACH INDICATION 9.2.12 LOCATION UPDATING ACCEPT 9.2.13 LOCATION UPDATING REJECT 9.2.14 LOCATION UPDATING REQUEST 9.2.15 {% embed url="" %} The document referenced appears to be about the GSM technical specifications, focusing on various signaling messages such as IMSI Detach Indication, Location Updating Accept/Reject, and Location Updating Request. For detailed explanations of these messages, please refer to the [ETSI GSM 04.08 document](https://www.etsi.org/deliver/etsi_gts/04/0408/05.00.00_60/gsmts_0408v050000p.pdf). IMSI DETACH INDICATION 9.2.12: This message is sent by a mobile station to notify the network that it is detaching, helping to manage resources effectively. LOCATION UPDATING ACCEPT 9.2.13: This message confirms that the location update request from a mobile station has been successfully processed. LOCATION UPDATING REJECT 9.2.14: This message is sent when a location update request cannot be processed by the network, including a reason code. LOCATION UPDATING REQUEST 9.2.15: This message is sent by a mobile station to update its location in the network.