diff --git a/Casks/m/microsoft-auto-update.rb b/Casks/m/microsoft-auto-update.rb
index 76a1e3d5b4..c27d31ddb8 100644
--- a/Casks/m/microsoft-auto-update.rb
+++ b/Casks/m/microsoft-auto-update.rb
@@ -4,8 +4,8 @@ cask "microsoft-auto-update" do
     sha256 "f638f7e0da9ee659c323f2ede0f176804bfe9a615a8f8b6320bd2e69d91ef2b2"
   end
   on_sierra :or_newer do
-    version "4.65.23112617"
-    sha256 "627a672ffc610b33733c8c8399944eaa06a08944ed4159a46f6b1d71f9322263"
+    version "4.66.23121017"
+    sha256 "e1d0fb04740282af67235329cd3d51229168bdde69d57b38ecfeaf66969170fd"
   end
 
   url "https://officecdnmac.microsoft.com/pr/C1297A47-86C4-4C1F-97FA-950631F94777/MacAutoupdate/Microsoft_AutoUpdate_#{version}_Updater.pkg"