diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 4c8dab3..cfb20c4 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -60,7 +60,11 @@
 
 /* Error codes in range 0x0021-0x0025 */
 #define MBEDTLS_ERR_AES_BAD_INPUT_DATA                    -0x0021  /**< Invalid input data. */
+
+/* MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE is deprecated and should not be used. */
 #define MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE               -0x0023  /**< Feature not available. For example, an unsupported AES key size. */
+
+/* MBEDTLS_ERR_AES_HW_ACCEL_FAILED is deprecated and should not be used. */
 #define MBEDTLS_ERR_AES_HW_ACCEL_FAILED                   -0x0025  /**< AES hardware accelerator failed. */
 
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \