diff --git a/docs/examples/sessioninfo.c b/docs/examples/sessioninfo.c
index d137c4bfc..98bf2bfd8 100644
--- a/docs/examples/sessioninfo.c
+++ b/docs/examples/sessioninfo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -31,6 +31,7 @@
 
 #include <curl/curl.h>
 #include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
 
 static CURL *curl;