Do I need to reinstall GOexchange when upgrading Microsoft Exchange?

This depends on how you are accomplishing the upgrade.

Exchange Upgrade on SAME hardware

If you are upgrading to a newer version of Microsoft® Exchange on the same server, you do not need to reinstall GOexchange®.  It will continue to function normally with the newer version of Microsoft® Exchange.

Exchange Upgrade/Migration to NEW hardware

If you are migrating the existing server to a newer version of Microsoft® Exchange on a new server, you must contact tech support and run through the Revoke/Transfer License process.