Most of the major UPS and PDU vendors have supported IPv6 for a while now. From what I hear from users, while some are using IPv6, most users are still using IPv4 to connect to their UPSes and PDUs.
I have some hunches on why that is, but I wanted to hear from the community to see what you're doing in practice.
So, do you use IPv4 or IPv6 to connect to your UPSes and PDUs?
For the comments: If you have a preference for one or the other: why?
If you're using hostnames/FQDNs, answer for whatever the name resolves to for you.