diff --git a/docs-mini/README.digitalfilters b/docs-mini/README.digitalfilters
index dce9a80dd..9f65b8ae9 100644
--- a/docs-mini/README.digitalfilters
+++ b/docs-mini/README.digitalfilters
@@ -1,3 +1,9 @@
+NOTE:
+This manual may contain outdated information. For documentation of the most recent features
+refer to
+http://wiki.flightgear.org/index.php/Howto:_Design_an_autopilot
+http://wiki.flightgear.org/index.php/Autopilot_Configuration_Reference
+
 COMMON SETTINGS
 ==============================================================================