The version header is no longer needed and a potential attack vector. Has now been removed - Work item: 30989

src/umbraco.businesslogic/UmbracoSettings.cs

@@ -311,28 +311,6 @@ namespace umbraco
             }
         }
 
-        /// <summary>
-        /// Gets a value indicating whether umbraco shouldn't add X-Umbraco-Version to the http header.
-        /// </summary>
-        /// <value><c>true</c> if umbraco will not add header; otherwise, <c>false</c>.</value>
-        public static bool RemoveUmbracoVersionHeader
-        {
-            get
-            {
-                try
-                {
-                    bool result;
-                    if (bool.TryParse(GetKey("/settings/requestHandler/removeUmbracoVersionHeader"), out result))
-                        return result;
-                    return false;
-                }
-                catch
-                {
-                    return false;
-                }
-            }
-        }
-
         /// <summary>
         /// This will add a trailing slash (/) to urls when in directory url mode
         /// NOTICE: This will always return false if Directory Urls in not active

src/umbraco.presentation/config/umbracoSettings.Release.config

@@ -124,8 +124,6 @@
             <char org="Ä">ae</char>
             <char org="Ö">oe</char>
         </urlReplacing>
-
-        <removeUmbracoVersionHeader>false</removeUmbracoVersionHeader>
     </requestHandler>
 
     <templates>

src/umbraco.presentation/default.aspx.cs

@@ -206,10 +206,6 @@ namespace umbraco
             if (!UmbracoSettings.UseAspNetMasterPages)
                 initUmbracoPage();
             base.OnInit(e);
-
-            // Add Umbraco header
-            if (!UmbracoSettings.RemoveUmbracoVersionHeader)
-                Response.AddHeader("X-Umbraco-Version", string.Format("{0}.{1}", GlobalSettings.VersionMajor, GlobalSettings.VersionMinor));
         }
 
         private void initUmbracoPage()