diff --git a/C4S_UPDATE b/C4S_UPDATE
index 0de2061fb..64eb0fbc1 100644
--- a/C4S_UPDATE
+++ b/C4S_UPDATE
@@ -1,24 +1,29 @@
 Update c4science branch from upstream
 -------------------------------------
 
 # Get changes and merge
 git fetch upstream
 git merge --squash upstream/stable
 
 # Fix conflict
 vim $(grep -rl '<<<<<<<' --exclude-dir=.git)
 
 # Copy files from upstream if needed
 for i in $(grep -rl '<<<<<<<' --exclude-dir=.git); do 
     grep -rnl c4s $i > /dev/null || cp ../PH-UPSTREAM/$i $i
 done
 
 # Commit and push
 git commit -am "Merge with Stable Week XXX"
 git push origin stable
 
+DEBUG
+-----
+
+# Check all the differences with the upstream branch
+git diff upstream/stable..HEAD
 
 TODO
 ----
 
 - Tester git rerere