With the release of ArcGIS 10.1 we have been busy helping customers with licensing.
ArcGIS for Desktop 10.1 provides the ability to upgrade a currently installed and authorised system from ArcGIS for Desktop 10 to ArcGIS for Desktop 10.1.
This applies for both concurrent and single use licenses. A walk-through is now available to help customers when upgrading licenses.
ArcGIS for Server 10.1 licenses cannot be upgraded and new ECP files are required to authorise the ArcGIS for Server 10.1.