A brief summary of the issue we are experiencing:

Talking to a Subversion server 1.8 using jenkins subversion plugin ver2.9, we encounter an old issue of working copy formats being incompatible.

Checking out from a Subversion 1.8 working copy format does not work due to the svnkit that is used in the subversion plugin ver 2.9 which seemingly doesn't support Subversion 1.8 working copy format.

Would patching the subversion plugin ver2.9 with svnkit ver1.9.0 address the issue which keeps on recurring ?