diff --git a/include/osmocom/gsm/gsm0411_smr.h b/include/osmocom/gsm/gsm0411_smr.h
index 5ea8584..b061492 100644
--- a/include/osmocom/gsm/gsm0411_smr.h
+++ b/include/osmocom/gsm/gsm0411_smr.h
@@ -11,6 +11,7 @@
 #define GSM411_SM_RL_REPORT_IND		0x406
 
 struct gsm411_smr_inst {
+	uint64_t id;		/* a unique id for the SMS */
 	int network;		/* is this a MO (0) or MT (1) transfer */
 	int (*rl_recv) (struct gsm411_smr_inst *inst, int msg_type,
 			struct msgb *msg);
@@ -24,7 +25,7 @@
 extern const struct value_string gsm411_rp_cause_strs[];
 
 /* init a new instance */
-void gsm411_smr_init(struct gsm411_smr_inst *inst, int network,
+void gsm411_smr_init(struct gsm411_smr_inst *inst, uint64_t id, int network,
 	int (*rl_recv) (struct gsm411_smr_inst *inst, int msg_type,
 			struct msgb *msg),
 	int (*mn_send) (struct gsm411_smr_inst *inst, int msg_type,