Copy a old board layout into KiCAD

[John_Pateman]

Sure you can use the 5.1.x libraries but the library format has changed in 5.99 and, presumably new development will be on this not on 5.1.

KiCad nightly (v5.99): New schematic and symbol library file formats are now the default

The new s-expression schematic and symbol library file formats are now the default and should be available as soon as the nightly builds are complete. All new schematics and symbol libraries will be created using the new file formats. All existing schematics will be converted to the new file format on the first load and all subsequent changes will be made to the new file format. The old schematic files remain unchanged and no further edits will be made made. It is still a good idea to make a…