diff --git a/documentation/language-reference/domain-modifiers/M365_BUILDER.md b/documentation/language-reference/domain-modifiers/M365_BUILDER.md
index ca7a9aa887..1db0361798 100644
--- a/documentation/language-reference/domain-modifiers/M365_BUILDER.md
+++ b/documentation/language-reference/domain-modifiers/M365_BUILDER.md
@@ -13,6 +13,7 @@ parameters_object: true
 parameter_types:
   label: string?
   mx: boolean?
+  mxHost: string?
   autodiscover: boolean?
   dkim: boolean?
   skypeForBusiness: boolean?