An upgrade to Defender 5.9.1 is possible from Defender 5.8.2 or Defender 5.8.1 only. If you have Defender 5.7 or earlier deployed, a direct upgrade to Defender 5.9.1 is not supported and may cause your Defender components to stop functioning properly, if attempted. Please upgrade your Defender 5.7 or earlier components to Defender 5.8.2 first and then upgrade them to Defender 5.9.1. See the Release Notes for details.
Defender enhances security by using two-factor authentication to authenticate the users who request access to valuable resources within your organization. Defender uses your current identity store within Microsoft® Active Directory® to enable two-factor authentication, taking advantage of its inherent scalability and security, and eliminating the costs and time involved to set up and maintain proprietary databases. Defender’s Web-based administration and user self-service ease the implementation of two-factor authentication for both administrators and users. Defender 5.8.2 is a minor release, with enhanced features and functionality.