diff --git a/lib/http2.c b/lib/http2.c
index c6588b5773292235a006380f6950aba3b375653e..ba088b7127c1a401ff0eca46b2650e2332365ac4 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -37,6 +37,10 @@
 /* include memdebug.h last */
 #include "memdebug.h"
 
+#if (NGHTTP2_VERSION_NUM < 0x000300)
+#error too old nghttp2 version, upgrade!
+#endif
+
 /*
  * HTTP2 handler interface. This isn't added to the general list of protocols
  * but will be used at run-time when the protocol is dynamically switched from