diff --git a/changelog.html b/changelog.html
index 1adcee0fd349bd10b3b685d7f5cf716b16d8f305..9f110f355641a641a71a459bb3c56d3a9a68cc75 100644
--- a/changelog.html
+++ b/changelog.html
@@ -55,7 +55,9 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
-  <li class=>
+  <li class="rfe">
+    API changes: Add a reusable implementation of <code>IdleOfflineCause</code> class.
+    (<a href="https://github.com/jenkinsci/jenkins/commit/7e05b5032e138b5780eabc790d7cddecdc9b0b7c">commit 7e05b50</a>)
 </ul>
 </div><!--=TRUNK-END=-->
 <h3><a name=v1.643>What's new in 1.643</a> (2015/12/20)</h3>
diff --git a/core/src/main/java/hudson/slaves/OfflineCause.java b/core/src/main/java/hudson/slaves/OfflineCause.java
index b13361a20683dc7eb6b8a68b48cfed2d68f79086..7f7704d712162073f05e9ef300f155391d30323a 100644
--- a/core/src/main/java/hudson/slaves/OfflineCause.java
+++ b/core/src/main/java/hudson/slaves/OfflineCause.java
@@ -158,7 +158,7 @@ public abstract class OfflineCause {
 
     /**
      * Caused by idle period.
-     * @since TODO
+     * @since 1.644
      */
     public static class IdleOfflineCause extends SimpleOfflineCause {
         public IdleOfflineCause () {