diff --git a/docs/ApiValidationRules.md b/docs/ApiValidationRules.md
index 40788b7..c080ae0 100644
--- a/docs/ApiValidationRules.md
+++ b/docs/ApiValidationRules.md
@@ -105,7 +105,7 @@ Usually the "Z" is missing at the end indicating local time.
     | tidal_window_from | value must be in the future |
     | tidal_window_to | value must be in the future, value must be > tidal_window_from |
     | recommended_tugs | 0 < value < 10 |
-    | canceled | may not be set on POST |
+    | canceled | optional on POST |
     | evaluation | may not be set |
     | evaluation_message | may not be set |
     | created / modified | may not be set |