docs: Updates for DP4 release

- note final SDK is available
- update links to DP4 release notes

Change-Id: Id56b4bc9673f7ad12212d67045dc18fb9c72a6e8
diff --git a/docs/html/index.jd b/docs/html/index.jd
index c69acab..b1248af 100644
--- a/docs/html/index.jd
+++ b/docs/html/index.jd
@@ -22,6 +22,7 @@
       <a href="{@docRoot}preview/index.html">
         <h1 class="dac-hero-title">Android N Developer Preview</h1>
         <p class="dac-hero-description">
+          <strong>Android N final SDK is now available!</strong>
           Get ready for the next version of Android!
           <strong>Test your apps</strong> on Nexus and other devices. Support new system
           behaviors to <strong>save power and memory</strong>.
diff --git a/docs/html/preview/index.jd b/docs/html/preview/index.jd
index 0b21e68..241a98e 100644
--- a/docs/html/preview/index.jd
+++ b/docs/html/preview/index.jd
@@ -24,6 +24,7 @@
       <div class="col-7of16 col-push-9of16" style="padding-left:2em">
         <h1 class="dac-hero-title">Android N Developer Preview</h1>
         <p class="dac-hero-description">
+          <strong>Android N final SDK is now available!</strong>
           Get ready for Android N!
           <strong>Test your apps</strong> on Nexus and other devices. Support new system
           behaviors to <strong>save power and memory</strong>.
diff --git a/docs/html/preview/overview.jd b/docs/html/preview/overview.jd
index 1b45c1a..faf48b8 100644
--- a/docs/html/preview/overview.jd
+++ b/docs/html/preview/overview.jd
@@ -5,25 +5,26 @@
 page.tags="preview", "developer", "android"
 
 @jd:body
+
 <!--
 <div class="cols" style=
-"background-color:#f2daf5; padding: 5px 0;margin-bottom:1em; text-align:center;">
+"background-color:#B2DFDB; padding: 5px 0;margin-bottom:1em; text-align:center;">
 <h3>
-    Developer Preview 3 is now available
+    Developer Preview X is now available
   </h3>
-  <p>Includes final SDK and near-final system images</p>
+  <p>This release includes the ...</p>
    <div style="margin:auto 1em">
  <ul class="dac-section-links">
     <li class="dac-section-link">
-      <a href="{@docRoot}preview/support.html#preview3-notes">
+      <a href="{@docRoot}preview/support.html#dp4">
       <span class="dac-sprite dac-auto-chevron"></span>
       Read the Notes</a>
     </li>
 
     <li class="dac-section-link">
-      <a href="{@docRoot}preview/support.html#preview3-get">
+      <a href="{@docRoot}preview/download.html">
       <span class="dac-sprite dac-auto-chevron"></span>
-      Get the Update</a>
+      Test the Update</a>
     </li>
 
     <li class="dac-section-link">
@@ -137,13 +138,14 @@
 -->
 
 <h2 id="timeline">Timeline and updates</h2>
-<img src="{@docRoot}images/n-preview-updates_2x.png">
 
 <p>
   The N Developer Preview runs from 9 March 2016 until the final Android N
   public release to AOSP and OEMs, planned for Q3 2016.
 </p>
 
+<img src="{@docRoot}images/n-preview-updates_2x.png">
+
 <p>
   At key development milestones, we’ll deliver updates for your development and
   testing environment. In general you can expect an update each month (4 to 6
@@ -154,7 +156,7 @@
   <li><strong><a href="{@docRoot}preview/support.html#dp1">Preview 1</a></strong> (initial release, alpha)</li>
   <li><strong><a href="{@docRoot}preview/support.html#dp2">Preview 2</a></strong> (incremental update, alpha)</li>
   <li><strong><a href="{@docRoot}preview/support.html#dp3">Preview 3</a></strong> (incremental update, beta)</li>
-  <li><strong>Preview 4</strong> (final APIs and official SDK, Play publishing)</li>
+  <li><strong><a href="{@docRoot}preview/support.html#dp4">Preview 4</a></strong> (final APIs and official SDK, Play publishing)</li>
   <li><strong>Preview 5</strong> (near-final system images for final testing)</li>
   <li><strong>Final release</strong> to AOSP and ecosystem</li>
 </ul>