The licenses are connected to the MAC addresses of the clients. You can see this if you open the license file.
You will find the related MAC address in the license script:
At first you have to find out which clients need the new license. The MAC addresses should then be mailed to IGEL Technology GmbH and IGEL will return the license ready to be rolled out automatically via the UMS.
IGEL will send you the new license files with the relevant MAC addresses integrated.
When you restart the thin client the new license will be rolled out to the selected devices.