Notes how to uppgrade Umbraco.
From version 4.0.0
To 4.0.2.1
1) Make a backup of your site (including the database).
2) Download the latest Umbraco package from
umbraco.org/download.
3) Copy the files bin, umbraco, umbraco_client, install to your site root.
4) Access your site and the upgrade wizard appears.