We need to update our use of seraph to delegate the definition of the logout url to seraph-config.xml

Workaround for Confluence 5.7.2 and older

1. Find and copy <confluence_install>/confluence/WEB-INF/lib/confluence-x.x.x.jar to a temp location (with "x.x.x" representing your Confluence version number)
2. Extract the file: jar -xf confluence-x.x.x.jar
3. Open xwork.xml in an editor and locate this section:

   <action name="logout" class="com.atlassian.confluence.user.actions.LogoutAction">
               <interceptor-ref name="defaultStack"/>
               <result name="error" type="velocity">/logout.vm</result>
               <result name="success" type="redirect">/login.action?logout=true</result>
           </action>
   

4. Replace the redirect URL for success result to the desired URL, e.g.:

               <result name="success" type="redirect">/my_custom_url.html</result>
   

5. Save the file, and copy it to <confluence_install>/confluence/WEB-INF/classes/
6. Restart Confluence