diff --git a/src/test/java/net/hostsharing/hsadminng/hs/office/scenarios/README.md b/src/test/java/net/hostsharing/hsadminng/hs/office/scenarios/README.md
index 037b151a..e8384ba2 100644
--- a/src/test/java/net/hostsharing/hsadminng/hs/office/scenarios/README.md
+++ b/src/test/java/net/hostsharing/hsadminng/hs/office/scenarios/README.md
@@ -76,9 +76,16 @@ Use `${...}` for placeholders which need to be replaced with JSON quotes
 `%{...}` for placeholders which need to be rendered raw
 and `&{...}` for placeholders which need to get URI-encoded.
 
+If `???` is added before the closing brace, the property is optional.
+This means, if it's not available in the properties, `null` is used.
+
 Properties with null-values are removed from the JSON.
 If you need to keep a null-value, e.g. to delete a property,
-use `NULL` (all caps).
+use `NULL` (all caps) in the template (not the variable value).
+
+A special syntax is the infix `???`-operator like in: `${%{var1???}???%{var2???}%{var3???}}`.
+In this case the first non-null value is used.
+
 
 
 ### The Use-Case Verification