diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 2ac2cc6..c930a8f 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1266,7 +1266,7 @@
  * which is currently hard-coded to be int32_t.
  *
  * Note that this option is meant for internal use only and may be removed
- * without notice.
+ * without notice. It is incompatible with PSA_USE_PSA_CRYPTO.
  */
 //#define MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER