If you look in $FGLDIR/bin, you will see in amongst fglcomp, fglform, fglrun, a script/executable named "fglWrt". fglWrt is known as the "License Controller".
The License Controller is called by the compilation and runner programs to verify that the installation is correctly licensed and that the compilation and runner programs can execute.
When upgrading the Four Js License Manager, you may need to upgrade or Patch the License Controller.
To read more on the License Controller and why and how you may need to "Patch" it, read
https://4js.com/ask-reuben/ig-97/