Why is the option 'Request temporary licenses' not available?

The function ‘Request temporary licenses’ is only available on systems with an empty license overview.

The function ‘Request temporary licenses’ is only included in AppService version 2.3.51.704 or higher.  Install the latest AppService:
https://customercare.gmgcolor.com/hc/en-us/articles/14136588212123-Install-latest-AppService-version

The required AppService is only included in new setups (e.g. GMG OpenColor 3.1.5.9). 
To use this functionality in older products, please open the license overview in this way:
https://customercare.gmgcolor.com/hc/en-us/articles/23131587382939-How-to-open-the-new-license-window-in-old-software-versions