diff --git a/include/mbedtls/error.h b/include/mbedtls/error.h
index 39cd67f..0c38889 100644
--- a/include/mbedtls/error.h
+++ b/include/mbedtls/error.h
@@ -80,7 +80,7 @@
  * CHACHA20  3                  0x0051-0x0055
  * POLY1305  3                  0x0057-0x005B
  * CHACHAPOLY 2 0x0054-0x0056
- * PLATFORM  1  0x0070-0x0070
+ * PLATFORM  1  0x0070-0x0072
  *
  * High-level module nr (3 bits - 0x0...-0x7...)
  * Name      ID  Nr of Errors
diff --git a/include/mbedtls/platform.h b/include/mbedtls/platform.h
index 5cd143c..89fe8a7 100644
--- a/include/mbedtls/platform.h
+++ b/include/mbedtls/platform.h
@@ -43,7 +43,8 @@
 #include "platform_time.h"
 #endif
 
-#define MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED       -0x0070 /**< Hardware accelerator failed */
+#define MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED     -0x0070 /**< Hardware accelerator failed */
+#define MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED -0x0072 /**< The requested feature is not supported by the platform */
 
 #ifdef __cplusplus
 extern "C" {