Prepare release 2.6

Change-Id: I2e73f2ec31f07076f0abba557d23c5ec79bc8915
diff --git a/docs/source/_templates/indexcontent.html b/docs/source/_templates/indexcontent.html
index ac24170..4120c16 100644
--- a/docs/source/_templates/indexcontent.html
+++ b/docs/source/_templates/indexcontent.html
@@ -59,8 +59,9 @@
       <td width="50%" valign="top">
         <h2>ndnSIM Versions</h2>
         <div class="tile">
-          <p class="biglink"><a class="biglink" href="#">ndnSIM 2.5</a><br/>
+          <p class="biglink"><a class="biglink" href="#">ndnSIM 2.6</a><br/>
             <span class="linkdescr">latest version</span></p>
+          <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.5/">ndnSIM 2.5</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.4/">ndnSIM 2.4</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.3/">ndnSIM 2.3</a><br/>
           <p class="biglink"><a class="biglink" href="http://ndnsim.net/2.2/">ndnSIM 2.2</a><br/>