Don't know if this library is still maintained, but as of September 2020 there is an update to jdiff that produces slightly different patch files.
https://sourceforge.net/projects/jojodiff/files/
Existing diff-files will be handled correctly by the new version,
but diff-files from the new version will not be handled correctly by previous versions !```
I write my own implementation of JPatch for C# - I am still looking into seeing what's changed, but I think it should be noted that unless the patch code is updated, implementations of jpatch/janpatch may not work with the latest version of jdiff.
Don't know if this library is still maintained, but as of September 2020 there is an update to jdiff that produces slightly different patch files. https://sourceforge.net/projects/jojodiff/files/