Normally we suggest letting one of our certified techs do this upgrade so it goes smoothly.  Open a Ticket for DidItBetter Support 

• Stop Add2Exchange Standard Edition
• Uninstall Add2Exchange Standard
• Download  Enterprise Edition, All Other Upgrades
• Install Enterprise Upgrade
• Do Diags before opening up Console
  • Do Santize Database test in tools and if > 0 then delete bad rows
• Open Add2Exchange Enterprise Console
• Re-License by submitting a new license request :
  • Product Activation: License Key Instructions after Purchase
  • Potentially set up Templates or GAL Sync or Possibly Convert to RGM  - talk to technical support by opening a ticket

YTD

Discuss updates:  policy to download and notify, and do MS critical updates