Acro Package support is broken

The support for the acronym package acro was added 5 years ago in 1cd0b81a and wasn't changed from then on. But it is mentioned in the manual.

In version 3 of acro (released in 2020), the styling commands changed completely. So the ones currently in use in ifiseries.sty don't work anymore. So if I try to use this style together with acro and a somewhat recent tex distribution, my document won't compile anymore.

I think the easiest fix is to force the use of acro version 2 by changing line 280 in ifiseries.sty to \RequirePackage{acro}[=v2]%.