diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 7daba37..509eeab 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1548,6 +1548,20 @@
 #define MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 
 /**
+ * \def MBEDTLS_SSL_RECORD_SIZE_LIMIT
+ *
+ * Enable support for RFC 8449 record_size_limit extension in SSL.
+ *
+ * \warning This extension is currently in development and must NOT be used except
+ *          for testing purposes.
+ *
+ * Requires: MBEDTLS_SSL_PROTO_TLS1_3
+ *
+ * Uncomment this macro to enable support for the record_size_limit extension
+ */
+//#define MBEDTLS_SSL_RECORD_SIZE_LIMIT
+
+/**
  * \def MBEDTLS_SSL_PROTO_TLS1_2
  *
  * Enable support for TLS 1.2 (and DTLS 1.2 if DTLS is enabled).