Thank you for working on this! One note: where is it documented how ipupdown and ipupdown-ng interact? For example using the alternatives system, or a different config file location, or some sort of tagging mechanism in network/interfaces. I would appreciate it if this was in the changelog, at a minimum, and maybe other people would too? A brief "...by using $method" seems like it would be enough.
Kind regards,
Nicholas
P.s. sorry for the html part, I'm on my phone