IPv6

IPv6 support was added in version 3.2

Additional Prerequisites

Socket6.pm
fping6
the standard fping will only do IPv4. the fping from fping.com can be compiled to do either v4 or v6, it cannot do both in one binary. you must install one fping for v4 and one for v6.
an operating system with IPv6 support.

Basically, do nothing.

If the address you specify is an IPv6 address, or resolves to an IPv6 address, IPv6 will be used. There is nothing to configure differently.