Should be 6-7.

doc/install/installation.md

@@ -173,7 +173,7 @@ We recommend using a PostgreSQL database. For MySQL check [MySQL setup guide](da
 ## Clone the Source
 
     # Clone GitLab repository
-    sudo -u git -H git clone https://gitlab.com/gitlab-org/gitlab-ce.git -b 6-6-stable gitlab
+    sudo -u git -H git clone https://gitlab.com/gitlab-org/gitlab-ce.git -b 6-7-stable gitlab
 
     # Go to gitlab dir
     cd /home/git/gitlab