Do firmware-updates delete custom settings?

[pwp]

My rapidly emerging favorite video camera is the Panasonic GH4. Mine runs firmware V 1.1.
Firmware V 2.1 is available.

My GH4 is fully set up with complex, evolved custom settings in the C1-C3 options. I'd hate to lose these.
Do firmware updates over-ride or delete custom settings?

-pw