title: Can CISCO ASA hot standby if their firmware version is different?
body: <p>I have a pair of Active/Standby ASA need to upgrade from 9.1.5 to 9.1.7.<br/>
  I am going to upgrade the Standby unit first and then force it to become active.<br/>
  In case of any unpredictable problem on version 9.1.7.<br/>
  I want to wait for a week before upgrading another the another ASA.<br/>
  My concern is this pair of ASA can't perform hot standby due to the version difference.</p>