diff --git a/docs/_includes/navigation.html b/docs/_includes/navigation.html
index 5a1ebe313..247608183 100755
--- a/docs/_includes/navigation.html
+++ b/docs/_includes/navigation.html
@@ -17,7 +17,7 @@
                     <label class="md-icon md-icon--menu md-header-nav__button" for=__drawer></label>
                 </div>
 
-                <div class="md-flex__cell md-flex__cell--stretch">
+                <div class="md-flex__cell md-flex__cell--shrink">
                     <a class="md-header-nav__button md-logo" href="{{ site.url }}{{ site.baseurl }}/" title="{{ site.title }}">
                     <div class="md-flex__ellipsis md-header-nav__title" data-md-component=title>
                         <span class=md-header-nav__topic>{{ site.title }}</span>
@@ -25,6 +25,19 @@
                     </a>
                 </div>
 
+                <div class="md-flex__cell md-flex__cell--shrink">
+                  <div class="md-header-nav__source">
+                    <div class="dropdown version-switch">
+                      <a class="dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+                      </a>
+                      <div class="dropdown-menu">
+                        <!-- a class="dropdown-item" href="#">Stable</a -->
+                        <!-- div class="dropdown-divider"></div -->
+                      </div>
+                    </div>
+                  </div>
+                </div>
+
                 <div class="md-flex__cell md-flex__cell--shrink">
                   <div class="md-header-nav__source">
                     <a class="md-source" href="{{ site.baseurl }}/docs/using-turing/get-started" title="Go to Get Started">
diff --git a/docs/_includes/sidebar.html b/docs/_includes/sidebar.html
index 8b972180b..02ea0a12b 100644
--- a/docs/_includes/sidebar.html
+++ b/docs/_includes/sidebar.html
@@ -27,13 +27,19 @@
 
                 <div class="md-nav__source">
                     <a class="md-source" data-md-source="github" href="{{ site.repo }}" title="Go to repository">
-                    <div class="md-source__icon">
+                    <span class="md-source__icon">
                         <i class="fa fa-github fa-3x"></i>
-                    </div>
-                    <div class="md-source__repository">
+                    </span>
+                    <span class="md-source__repository">
                       {{ site.github_user }}/{{ site.github_repo }}
-                    </div></a>
-                  </div>
+                    </span></a>
+                </div>
+
+                <div class="md-nav__dropdown">
+                  <select id="version-selector">
+                    <!-- option value="#" selected="selected">v 0.5.1</option -->
+                  </select>
+                </div>
 
               <label class="md-nav__title" for="__drawer"></label>
 
diff --git a/docs/_layouts/default.html b/docs/_layouts/default.html
index a9f309377..283e77782 100755
--- a/docs/_layouts/default.html
+++ b/docs/_layouts/default.html
@@ -4,22 +4,22 @@
     <meta charset="utf-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
     <meta http-equiv="content-language" content="en">
-  
+
     <meta name="viewport" content="width=device-width, initial-scale=1">
-  
+
     <title>{% if page.title %}{{ page.title }}{% else %}{{ site.title }}{% endif %}</title>
     <meta name="description" content="{% if page.excerpt %}{{ page.excerpt | strip_html | strip_newlines | truncate: 160 }}{% else %}{{ site.description }}{% endif %}">
     {% if site.author %}<meta name="author" content="{{ site.author }}">{% endif %}
-    <meta name="theme-color" content="{{ site.themeColor }}">    
+    <meta name="theme-color" content="{{ site.themeColor }}">
     <link href="https://fonts.gstatic.com" rel="preconnect" crossorigin>
-  
+
     <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,400i,700|Roboto+Mono">
     <style>body,input{font-family:"Roboto","Helvetica Neue",Helvetica,Arial,sans-serif}code,kbd,pre{font-family:"Roboto Mono","Courier New",Courier,monospace}</style>
-  
+
     <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
     <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
     <link rel="alternate" type="application/rss+xml" title="{{ site.title }}" href="{{ "/feed.xml" | prepend: site.baseurl | prepend: site.url }}">
-    <meta name="lang:clipboard.copy" content="Copy to clipboard">      
+    <meta name="lang:clipboard.copy" content="Copy to clipboard">
     <meta name="lang:clipboard.copied" content="Copied to clipboard">
     <meta name="lang:search.language" content="en">
     <meta name="lang:search.pipeline.stopwords" content="True">
@@ -27,25 +27,27 @@
     <meta name="lang:search.result.none" content="No matching documents">
     <meta name="lang:search.result.one" content="1 matching document">
     <meta name="lang:search.result.other" content="# matching documents">
-    <meta name="lang:search.tokenizer" content="[\s\-]+">  
+    <meta name="lang:search.tokenizer" content="[\s\-]+">
+    <script src="/versions.js"></script>
     <script src="{{ site.baseurl }}/assets/js/modernizr.74668098.js"></script>
-    <link rel="shortcut icon" href="{{ site.baseurl }}/assets/img/favicon.ico"> 
+    <link rel="shortcut icon" href="{{ site.baseurl }}/assets/img/favicon.ico">
     <link rel="stylesheet" href="{{ site.baseurl }}/assets/css/main.css">
     <link rel="stylesheet" href="{{ site.baseurl }}/assets/css/palette.css">
+    <link rel="stylesheet" href="{{ site.baseurl }}/assets/css/header.css">
 
     <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
-  
+
     {% if page.url == "/" %}
     <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
     <link rel="stylesheet" href="{{ site.baseurl }}/assets/css/index.css">
     {% endif %}
 
-  </head> 
+  </head>
 
   <body dir="ltr" data-md-color-primary="{{ site.themeColor }}" data-md-color-accent="{{ site.accentColor }}">
     {% include navigation.html %}
 
-    <div class="md-container">         
+    <div class="md-container">
         <main class="md-main">
             <div class="md-main__inner md-grid full-width" data-md-component="container">
             {% include sidebar.html %}
@@ -55,7 +57,7 @@
             </div>
         </main>
     </div>
-    
+
     {% include footer.html %}
 
     <script src="{{ site.baseurl }}/assets/js/application.js"></script>
@@ -68,7 +70,7 @@
     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
     <script src="{{ site.baseurl }}/assets/js/index.js"></script>
     {% endif %}
-    
+
     {% include headers.html %}
     {% include tags.html %}
     {% include scrolltop.html %}
diff --git a/docs/assets/css/header.css b/docs/assets/css/header.css
new file mode 100644
index 000000000..af4c7eab6
--- /dev/null
+++ b/docs/assets/css/header.css
@@ -0,0 +1,29 @@
+.md-header-nav__button.md-logo * {
+  position: inherit;
+}
+.md-header-nav .dropdown {
+  margin: 1.6rem 0 0 -2rem;
+}
+.md-flex__cell--shrink .dropdown-item, .md-flex__cell--shrink .dropdown-item:hover {
+  color:#262626;
+}
+.dropdown-toggle {
+  opacity: 0.6;
+}
+.dropdown-note {
+  display: block;
+  width: 100%;
+  padding: .25rem 1.5rem;
+  clear: both;
+  font-weight: 400;
+  color: #999;
+  text-align: inherit;
+  white-space: nowrap;
+  background-color: transparent;
+  border: 0;
+}
+.md-nav__dropdown {
+  display: block;
+  padding: 1.2rem;
+  text-align: center;
+}
\ No newline at end of file
diff --git a/docs/assets/js/index.js b/docs/assets/js/index.js
index 609c9f300..7a35d42fd 100644
--- a/docs/assets/js/index.js
+++ b/docs/assets/js/index.js
@@ -4,7 +4,7 @@ excluded_in_search: true
 ---
 $(document).ready(function(){
     $('.md-header').attr('data-md-state', 'none');
-    
+
     $(window).scroll(function() {
         if ($(window).scrollTop() > 20) {
             $('.md-header').attr('data-md-state', 'shadow');
@@ -12,4 +12,37 @@ $(document).ready(function(){
             $('.md-header').attr('data-md-state', 'none');
         }
     });
-});
\ No newline at end of file
+
+    if (typeof(window.DOC_VERSIONS) == "undefined") {
+        window.DOC_VERSIONS = ["dev"];
+    }
+    var url_parts = /(.*:\/\/[^/]+\/)(.+?)(\/.*)/.exec(window.location.href);
+
+    $(".dropdown > a").text(url_parts[2]);
+    $.each(DOC_VERSIONS, function(index, value) {
+        if(value == url_parts[2]) {
+            // mobile
+            $("select#version-selector").append(
+                $('<option value="' + value + '" selected="selected">' + value + '</option>'));
+            return;
+        }
+        // desktop
+        $(".dropdown > div.dropdown-menu").append(
+            $('<a class="dropdown-item" href="#">' + value + '</a>'));
+        // mobile
+        $("select#version-selector").append(
+            $('<option value="' + value + '">' + value + '</option>'));
+    });
+
+    $(".dropdown > div.dropdown-menu > a").on("click", function() {
+        var target_version = $(this).text().trim();
+        if (target_version == url_parts[2]) return;
+        window.location.href = url_parts[1] + target_version + url_parts[3];
+    });
+
+    $("select#version-selector").change(function() {
+        var target_version = $("select#version-selector option:selected").text();
+        if (target_version == url_parts[2]) return;
+        window.location.href = url_parts[1] + target_version + url_parts[3];
+    });
+});
diff --git a/docs/jekyll-build b/docs/jekyll-build
index 543fdd498..acdf4a036 100755
--- a/docs/jekyll-build
+++ b/docs/jekyll-build
@@ -8,7 +8,7 @@ cd $DIR
 bundle exec jekyll build > $OUTPUT 2>&1
 
 if [[ $? != 0 ]]; then
-    rm $OUTPUT
+    rm -fr $OUTPUT
     gem install bundler
     bundle install
 else