mac svn this client is too old to work with working copy

executng ant task svn 

<target name="svnversion">

    <exec executable="svnversion" outputproperty="svnversion" />

    <echo message="SVN Version: ${svnversion}"/>

</target>

------------------------------------------------------------------------

svnversion:

     [exec] Result: 1

     [echo] SVN Version: svn: E155021: This client is too old to work with the working copy at

     [echo] '/Users/hongsangbeom/Documents/workspace-kjb/OrchestraFrameworkAndroid_kjb' (format 31).

     [echo] You need to get a newer Subversion client. For more details, see

     [echo]   http://subversion.apache.org/faq.html#working-copy-format-change

os: osx svn client too old, i should update svn client.

svn --version

--------------------------------

svn, version 1.7.19 (r1643991)

to install follow link : http://www.blastar.biz/2014/10/20/upgrading-svn-to-1-8-9-on-osx-10-10-yosemite/

bash-3.2# svn --version

svn, version 1.8.9 (r1591380)

   compiled Apr  8 2015, 20:17:07 on x86_64-apple-darwin14.1.0