I guess I upgraded to a version too far in the future, because after the upgrade the site was crashed. I uninstalled the upgrade and the site works fine except it displays this error on every page:

Fatal error: Call to undefined method Controller::outputFooterItems() in /home4/firstci7/public_html/concrete/elements/footer_required.php on line 8

I would eventually like to upgrade to the current version, but the site is heavily used right now. Can anyone help me remove or fix this error?