This blog article will briefly describe the new URL filtering features in the updated AsyncOS 8.5.0 for the Cisco IronPort Email Security Appliance.
Before you upgrade to 8.5.5 (which is the latest OS as of this post), please check the upgrade path at the URL below:
http://www.cisco.com/c/dam/en/us/td/docs/security/esa/esa8-5-5/ESA_8-5-5_Release_Notes.pdf