diff --git a/include/industry_standard/spdm.h b/include/industry_standard/spdm.h
index 776c6c6ed54..6a1cb0d5d68 100644
--- a/include/industry_standard/spdm.h
+++ b/include/industry_standard/spdm.h
@@ -13,7 +13,7 @@
 
 #pragma pack(1)
 
-/* 4 means SPDM spec 1.0, 1.1, 1.2, 1.3, 1.4 */
+/* Encompasses SPDM specification versions 1.0, 1.1, 1.2, 1.3, 1.4 */
 #define SPDM_MAX_VERSION_COUNT 5
 #define SPDM_MAX_SLOT_COUNT 8
 #define SPDM_MAX_OPAQUE_DATA_SIZE 1024
@@ -62,6 +62,9 @@
 #define SPDM_KEY_PAIR_INFO 0x7C
 #define SPDM_SET_KEY_PAIR_INFO_ACK 0x7D
 
+/* SPDM response code (1.4) */
+#define SPDM_SLOT_MANAGEMENT_RESP 0x08
+
 /* SPDM request code (1.0) */
 #define SPDM_GET_DIGESTS 0x81
 #define SPDM_GET_CERTIFICATE 0x82
@@ -99,6 +102,9 @@
 #define SPDM_GET_KEY_PAIR_INFO 0xFC
 #define SPDM_SET_KEY_PAIR_INFO 0xFD
 
+/* SPDM request code (1.4) */
+#define SPDM_SLOT_MANAGEMENT 0x88
+
 /* SPDM message header*/
 typedef struct {
     uint8_t spdm_version;