[Haskell-cafe] building with stack, need some older versions for one library

I'm assembling a large stack project from various places. I just did "stack new", using the default resolver, copied in most of my code, and got it compiled. Except I'm stuck on one thing. I need to use the 'midi-0.2.2' library (reads/writes MIDI files). Its depends on older versions of the same of the core packages. What should I do now? Do I modify the LTS resolver to something older and then type "stack build" again? How can I find an appropriate resolver without hit-and-miss? Mike