Please see the release notes for ACS 5.8 that is the last version of ACS
Release Notes for Cisco Secure Access Control System 5.8 - Cisco
If you are installing ACS in a new deployment or in an existing deployment, you have to know that ACS is End of Life'd.
It would be good to think about migrating over to ISE soon that is the next generation ACS server. You can find all the neccessary information about the differences between ACS and ISE, EOL information, migration demo, Videos on how to plan, prepare and migrate ACS to ISE. A detailed how to doc that has step by step instruction to migrate
http://cs.co/acstoise
Thanks
Krishnan
