diff --git a/include/osmocom/gsm/protocol/gsm_08_58.h b/include/osmocom/gsm/protocol/gsm_08_58.h
index 57a8f68..89aafb8 100644
--- a/include/osmocom/gsm/protocol/gsm_08_58.h
+++ b/include/osmocom/gsm/protocol/gsm_08_58.h
@@ -572,6 +572,12 @@
 	RSL_MRPCI_PHASE_2PLUS	= 3,
 };
 
+/* 9.3.20 Release Mode */
+enum rsl_rel_mode {
+	RSL_REL_NORMAL		= 0,
+	RSL_REL_LOCAL_END	= 1,
+};
+
 /*! @} */
 
 #endif /* PROTO_GSM_08_58_H */