The primary reason for seeking older versions is the shift in SketchUp’s framework. Starting with , the library only supports SketchUp 2017 and newer .
These versions are no longer supported by modern LibFredo6 updates. Libfredo6 Old Version
It is critical to avoid unofficial "mirror" sites which may package plugins with malware. The developer has officially archived legacy versions for users of older software. LibFredo6 - SketchUcation The primary reason for seeking older versions is
Some older, unmaintained plugins may only function with the specific library environment provided by earlier LibFredo6 builds. Where to Safely Download Old Versions Libfredo6 Old Version