diff --git a/Library/Homebrew/cmd/update.rb b/Library/Homebrew/cmd/update.rb
index 6e340e3c40..68298fd523 100644
--- a/Library/Homebrew/cmd/update.rb
+++ b/Library/Homebrew/cmd/update.rb
@@ -125,7 +125,7 @@ class Updater
   end
 
   # Matches raw git diff format (see `man git-diff-tree`)
-  DIFFTREE_RX = /^:[0-7]{6} [0-7]{6} [0-9a-fA-F]{40} [0-9a-fA-F]{40} ([ACDMRT])\d{0,3}\t(.+?)(?:\t(.+))?$/
+  DIFFTREE_RX = /^:[0-7]{6} [0-7]{6} [0-9a-fA-F]{40} [0-9a-fA-F]{40} ([ACDMRTUX])\d{0,3}\t(.+?)(?:\t(.+))?$/
 
   def report
     map = Hash.new{ |h,k| h[k] = [] }