I had my job already set to "Emulate clean checkout"
I upgraded to v1.4 of the plugin
Set "Subversion Workspace Version" to 1.7
Cleaned out the workspace.

First build is successful, but now if I "Build Now" (with no svn changes) the project does not build because "All outputs are up-to-date".

This shouldn't be the case since all output files should have been deleted on build.

Note I also get AssertionError: appears to be using unpatched svnkit at jar:xxx/SVNEvent.class which is reported in JENKINS-13790