Index: app/views/wiki/show.html.erb
===================================================================
--- app/views/wiki/show.html.erb	(revision 17686)
+++ app/views/wiki/show.html.erb	(working copy)
@@ -99,4 +99,8 @@
   <%= render :partial => 'sidebar' %>
 <% end %>
 
+<% content_for :header_tags do %>
+  <%= robot_exclusion_tag unless @content.current_version? %>
+<% end %>
+
 <% html_title @page.pretty_title %>
Index: test/functional/wiki_controller_test.rb
===================================================================
--- test/functional/wiki_controller_test.rb	(revision 17686)
+++ test/functional/wiki_controller_test.rb	(working copy)
@@ -1182,4 +1182,17 @@
     attachment = Attachment.order('id DESC').first
     assert_equal Wiki.find(1).find_page('CookBook_documentation'), attachment.container
   end
+
+  def test_old_version_should_have_robot_exclusion_tag
+    @request.session[:user_id] = 2
+    # Old versions should not be indexed by search engines
+    get :show, :params => {:project_id => 'ecookbook', :id => 'CookBook_documentation', :version => '2'}
+    assert_response :success
+    assert_select 'head meta[name="robots"][content=?]', 'noindex,follow,noarchive'
+
+    # The current version
+    get :show, :params => {:project_id => 'ecookbook', :id => 'CookBook_documentation'}
+    assert_response :success
+    assert_select 'head meta[name="robots"]', false
+  end
 end