The upgrade of the License server is quite simple as the wizard will upgrade it automatically.
The only thing that is important to do prior to license server upgrade is to backup the lic file, just in case as a best practice.
So the 1st step is to launch the installer
the wizard screen will appear:
then the upgrade option will be on display :
will have to wait till the process is finish usually it takes around few minutes
that all for the install part just press finish no reboot need it
A check is need it to perform in order to see the that upgrade performed well. So a quick log on on the administrator console will do to check the version of the lic server and also see if all is ok.