Free and open source ad server OpenX is very easy to upgrade in last versions following the procedure below:
1) Login to your OpenX ad server instance
2) In upper right corner for "Working as..." choose Administrator account
3) You will be logged in as an administrator and info message will be displayed on the top of the page:
"You are now working as Administrator account"
4) Select "Product Updates" in left menu (the last menu item at the bottom)
5) Select Check for Updates to show the status of the current OpenX instance. This will show useful information about the current version of OpenX, and the versions of every part of the associated software bundle.
6) Select Manage Past Updates and Backups to display information about OpenX upgrade history, together with information about any existing backup tables. Here you can delete backups or "artifacts".