Subversion 1.8 is available but the SVN plugin doesn't support it. For example, Configure|Subversion Workspace Version only offers 1.4 thru 1.7.

https://issues.jenkins-ci.org/browse/JENKINS-18844 is related.

To summarize this instead of having to browse through all the comments:

• Talking to a Subversion 1.8 Server should work fine, however the local working copy will still be SVN <=1.7
• Checking out in Subversion 1.8 Working Copy format does not work, because the version of svnkit that is used in the Subversion plugin (1.7.10) does not support Subversion 1.8 Working Copy

Things that need to be done to make this work:

• svnkit 1.8.0 is available and provides support for Subversion 1.8, see http://svnkit.com/download.php
• Updating to this version and adding "1.8" to the checkbox in the Jenkins Server configuration should be most of what is needed to make it work
• Unfortunately the Subversion plugin uses a patched version of svnkit, see https://github.com/jenkinsci/svnkit, merging the patches and the newer svnkit requires probably some work, depending on the amount of changes in svnkit upstream
• As soon as org.jenkins-ci.svnkit is updated to 1.8.x, the Subversion plugin can upgrade to this and use Subversion 1.8 Working Copy format