Confluence 5.7 has reached end of life
Check out the [latest version] of the documentation
This page explains the recovery process should you mistakenly try to upgrade your Confluence installation to a version beyond your current license entitlement.
During an upgrade an obvious indication that your license has expired can be found in your log file. You will see a 'WARN' level entry similar to this:
[confluence.upgrade.impl.DefaultUpgradeManager] isUpgradeAllowed Your license is now outside of its support period. You need to renew the license before you can upgrade to this version of Confluence.
When you try to access the Confluence site in your browser, you will see the following warning screen: