diff --git a/h2_ssl.t b/h2_ssl.t
index 3a65aaf..99f32ad 100644
--- a/h2_ssl.t
+++ b/h2_ssl.t
@@ -89,10 +89,17 @@
 open STDERR, ">&", \*OLDERR;
 
 plan(skip_all => 'no ALPN negotiation') unless defined getconn();
-$t->plan(2);
+$t->plan(3);
 
 ###############################################################################
 
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.21.4');
+
+ok(!get_ssl_socket(['unknown']), 'alpn rejected');
+
+}
+
 like(http_get('/', socket => get_ssl_socket(['http/1.1'])),
 	qr/200 OK/, 'alpn to HTTP/1.1 fallback');