diff --git a/include/osmocom/core/logging.h b/include/osmocom/core/logging.h
index f1304f5..5ae38c7 100644
--- a/include/osmocom/core/logging.h
+++ b/include/osmocom/core/logging.h
@@ -152,7 +152,9 @@
 #define DLIUUP		-24	/*!< Osmocom IuUP layer */
 #define DLPFCP		-25	/*!< Osmocom Packet Forwarding Control Protocol */
 #define DLCSN1		-26	/*!< CSN.1 (Concrete Syntax Notation 1) codec */
-#define OSMO_NUM_DLIB	26	/*!< Number of logging sub-systems in libraries */
+#define DLM2PA		-27	/*!< Osmocom M2PA (libosmo-sigtran) */
+#define DLM2UA		-28	/*!< Reserved for future Osmocom M2UA (libosmo-sigtran) */
+#define OSMO_NUM_DLIB	28	/*!< Number of logging sub-systems in libraries */
 
 /* Colors that can be used in log_info_cat.color */
 #define OSMO_LOGCOLOR_NORMAL NULL