MY FC has 8 serial. But parameters has only 7 how to configure?

ArduCopter
1

My Flight controller has 8 serial port. But parameters list shows only to 7. What to do to add in and configure. Thanks in advance

2

Any solutions to configure serial8? My FC has 8 UART port but I only find up to serial7 on my parameters?

3

What FC are you using?