Create a backup of Wordpress first before you do anything.
Click "Please update now" on top of Wordpress.
Click "Update Automatically"
Enter FTP Password. Also make sure to have FTPS selected.
Click Proceed.
This may take a few minutes.
You may need to after it is successful to propagate the changes to all sites. You do this in Dashboard -> Updates.
If it gets stuck, after a few minutes and it says this: "Briefly unavailable for scheduled maintenance. Check back in a minute."
Go to FTP /public_html/ and delete the .maintenance file.
This means it probably didn't work.
You will need to do this manually.
http://codex.wordpress.org/Updating_WordPress (Manual Update section)
Download the latest version in zip format (if on Windows). Unzip it.
Go to /wp-content/plugins/ of the new Wordpress files and delete the akismet and hello dolly plugins.
Delete the old wp-admin and wp-includes directories from the Remote FTP Server.
Use DiffMerge (File Compare) on the old wp-config-sample.php and the new wp-config-sample.php
DiffMerge - http://www.sourcegear.com/diffmerge/downloads.html
Always keep a copy of the old Wordpress version, so you can do this.
Copy any new differences over to the old wp-config.php on the Remote FTP Server.
Upload all the new files and OVERWRITE the old files on the Remote FTP Server.
When done, delete the wp-config-sample.php on the Remote FTP Server.
Visit your main WordPress admin page at /wp-admin. You may be asked to login again.
If a database upgrade is necessary at this point, WordPress will detect it and give you a link to a URL like http://example.com/wordpress/wp-
admin/upgrade.php. Follow that link and follow the instructions. This will update your database to be compatible with the latest code.
