diff --git a/library/ssl_client.c b/library/ssl_client.c
index a975d6a..7acb725 100644
--- a/library/ssl_client.c
+++ b/library/ssl_client.c
@@ -963,7 +963,9 @@
                                                               buf_len,
                                                               msg_len));
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
         mbedtls_ssl_tls13_finalize_write_client_hello(ssl);
+#endif
 
     }