The question wasn't asking someone to update it!
I came here for some 3rd party information, by asking if anyone else used it.
From my experience, something like moo.dll has worked in every version of mIRC from when moo.ll was released.
I find it odd that this dll works fine on mIRC 6.21 and a few versions below but not on the latest release.
I can't think of any significant changes to make this happen.