Help restoring score saved in Nightly 4.2.0 back to Stable 4.1.1

While toying around with the new 4.2.0 nightly build to see if anything significantly new had been implemented, I inadvertently did a save/overwrite of my score and now cannot open it in 4.1.1

Is there a workaround to restore it to a version compatible with the latest stable 4.1.1

I tried exporting the score from 4.2.0 as a .mxl file, but it crashed upon trying to open it in 4.1.1

A Midi export works, but the score is so horribly altered that let's not even go there.

Any help would be deeply appreciated.