I agree, this is by far one of the most useful/mandatory mods. Looks like I'm not the brightest crayon in the box, I rebuilt the project and modified zzVersionChecker.cs: return Versioning.version_major == 1 && Versioning.version_minor == 0 && Versioning.Revision == 5; But in the end it turned out KSP refused to run because of KWRocketry, I still couldn't figure out which part but was able to save some of my manned ships with a minimum set of parts.