diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 61a1bad..c8a7827 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2848,7 +2848,8 @@
      *      MAY treat a ticket as valid for a shorter period of time than what
      *      is stated in the ticket_lifetime.
      */
-    ticket_lifetime %= 604800;
+    if( ticket_lifetime > 604800 )
+        ticket_lifetime = 604800;
     MBEDTLS_PUT_UINT32_BE( ticket_lifetime, p, 0 );
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket_lifetime: %u",
                                 ( unsigned int )ticket_lifetime ) );