Unfortunately, due to some pretty massive changes in the code used by
that extension, it isn’t trivial to have a version that is 4.2 and 4.0
compatible.
I already spent a few hours poking at it. If it’s something you rely
on, you could certainly work with us to get an engineer dedicated to
digging in and figuring it out, but I know I won’t be attempting to
solve this again until we either try to add it to core, or a client
approaches us about it.