diff --git a/openbsc/include/openbsc/db.h b/openbsc/include/openbsc/db.h
index d0c85ea..25c2aea 100644
--- a/openbsc/include/openbsc/db.h
+++ b/openbsc/include/openbsc/db.h
@@ -41,6 +41,7 @@
 					 enum gsm_subscriber_field field,
 					 const char *subscr);
 int db_sync_subscriber(struct gsm_subscriber *subscriber);
+int db_subscriber_expire(void *priv, void (*callback)(void *priv, long long unsigned int id));
 int db_subscriber_alloc_tmsi(struct gsm_subscriber *subscriber);
 int db_subscriber_alloc_exten(struct gsm_subscriber *subscriber);
 int db_subscriber_alloc_token(struct gsm_subscriber *subscriber, uint32_t* token);
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index ea9f601..feb692f 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -247,6 +247,9 @@
 	int T3122;
 	int T3141;
 
+	/* timer to expire old location updates */
+	struct osmo_timer_list subscr_expire_timer;
+
 	/* Radio Resource Location Protocol (TS 04.31) */
 	struct {
 		enum rrlp_mode mode;
diff --git a/openbsc/include/openbsc/gsm_subscriber.h b/openbsc/include/openbsc/gsm_subscriber.h
index 6cf8573..78f9710 100644
--- a/openbsc/include/openbsc/gsm_subscriber.h
+++ b/openbsc/include/openbsc/gsm_subscriber.h
@@ -38,6 +38,7 @@
 	char name[GSM_NAME_LENGTH];
 	char extension[GSM_EXTENSION_LENGTH];
 	int authorized;
+	time_t expire_lu;
 
 	/* Temporary field which is not stored in the DB/HLR */
 	uint32_t flags;
@@ -98,6 +99,7 @@
 
 int subscr_purge_inactive(struct gsm_network *net);
 void subscr_update_from_db(struct gsm_subscriber *subscr);
+void subscr_expire(struct gsm_network *net);
 
 /* internal */
 struct gsm_subscriber *subscr_alloc(void);