My customer has a Cisco WLC with version 22.214.171.124. They want to incorporate NAC but, they were told they need to have version 5.1. But. when they review cisco IOS page, it says they should be using version 126.96.36.199, which is the version customer already has. So we need to know if they actually have to upgrade or not. Also, is there a license that is needed for whatever version is supported?