Ah, I think I misinterpreted what you meant by "nothing works anymore". I thought you were saying that no old Go projects were usable with new Go compilers. I believe you that this particular project may not work with the current toolchain.
Ah, yes, that wasn't sufficiently clear in my text. In almost all projects I've done/used, go modules work fine and are nice. It is just this one library that I know ceased to work.