In general, the Microchip CDC driver was free to use.
"The CDC class has been implemented in Windows (since Windows 98), macOS and most Linux distributions. Since Windows 10, no extra information has to be given in the start-up sequence as the operating system now has a generic driver that will be used for CDC. To support older versions of Windows (Windows 7 and earlier), provide an .inf file that associates with the correct driver."
However, these will not support the high-speed bit-banged JTAG mode FTDI chips can perform with the right driver. =3
"The CDC class has been implemented in Windows (since Windows 98), macOS and most Linux distributions. Since Windows 10, no extra information has to be given in the start-up sequence as the operating system now has a generic driver that will be used for CDC. To support older versions of Windows (Windows 7 and earlier), provide an .inf file that associates with the correct driver."
However, these will not support the high-speed bit-banged JTAG mode FTDI chips can perform with the right driver. =3