diff --git a/include/osmocom/msc/ran_msg_a.h b/include/osmocom/msc/ran_msg_a.h
index 3ba081d..2d045b9 100644
--- a/include/osmocom/msc/ran_msg_a.h
+++ b/include/osmocom/msc/ran_msg_a.h
@@ -35,7 +35,8 @@
 int ran_a_decode_l2(struct ran_dec *ran_a, struct msgb *bssap);
 struct msgb *ran_a_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg);
 
-enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2);
+enum reset_msg_type bssmap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
+					struct msgb *l2, int *supports_osmux);
 struct msgb *bssmap_make_reset_msg(const struct sccp_ran_inst *sri, enum reset_msg_type type);
 struct msgb *bssmap_make_paging_msg(const struct sccp_ran_inst *sri, const struct gsm0808_cell_id *page_cell_id,
 				    const char *imsi, uint32_t tmsi, enum paging_cause cause);
diff --git a/include/osmocom/msc/ran_msg_iu.h b/include/osmocom/msc/ran_msg_iu.h
index 316a91c..3f3d61e 100644
--- a/include/osmocom/msc/ran_msg_iu.h
+++ b/include/osmocom/msc/ran_msg_iu.h
@@ -28,7 +28,8 @@
 int ran_iu_decode_l2(struct ran_dec *ran_dec_iu, struct msgb *ranap);
 struct msgb *ran_iu_encode(struct osmo_fsm_inst *caller_fi, const struct ran_msg *ran_enc_msg);
 
-enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, const struct msgb *l2);
+enum reset_msg_type ranap_is_reset_msg(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
+				       struct msgb *l2, int *supports_osmux);
 struct msgb *ranap_make_reset_msg(const struct sccp_ran_inst *sri, enum reset_msg_type type);
 struct msgb *ranap_make_paging_msg(const struct sccp_ran_inst *sri, const struct gsm0808_cell_id *page_cell_id,
 				   const char *imsi, uint32_t tmsi, enum paging_cause cause);
diff --git a/include/osmocom/msc/sccp_ran.h b/include/osmocom/msc/sccp_ran.h
index f84bf61..a4bd4ca 100644
--- a/include/osmocom/msc/sccp_ran.h
+++ b/include/osmocom/msc/sccp_ran.h
@@ -233,8 +233,11 @@
 
 	/* Return whether the given l2_cl message is a RESET, RESET ACKNOWLEDGE, or RESET-unrelated message.
 	 * This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),
-	 * it is not used in sccp_ran.c. */
-	enum reset_msg_type (* is_reset_msg )(const struct sccp_ran_inst *sri, const struct msgb *l2_cl);
+	 * it is not used in sccp_ran.c.
+	 * In supports_osmux, return 0 for no information, 1 for support detected, -1 for non-support detected.
+	 */
+	enum reset_msg_type (* is_reset_msg )(const struct sccp_ran_inst *sri, struct osmo_fsm_inst *log_fi,
+					      struct msgb *l2_cl, int *supports_osmux);
 
 	/* Return a RESET or RESET ACK message for this RAN type.
 	 * This callback is stored in struct sccp_ran_inst to provide RESET handling to the caller (ran_peer),