Can't Open MR 75 Year on my Mac

Like I say in the title, I can’t open my Model Railroader 75 Year collection on my Mac. It’s a newer (Intel chip) Mac. Would open fine on my old (PC chip) model. Now I get a director error and missing Xtra software. Any ideas?

We’re sorry, Mark, but as we announced a few months ago, when Apple updated their operating system they deprecated some of the support files that the software on our 75-year DVD needed to run. Since we purchased the software from a third-party vendor, rather than developing it in-house, we can’t patch it. It would require a complete rewrite of the software, which would cost us more than the original disc did. I’m afraid that the only workaround is to use it on a Windows computer or a Mac with a pre-upgrade operating system.