Apache Wicket 6.21.0 發布，現在使用語義版本來開發 Wicket，現已提供在 Maven：

<dependency>
    <groupId>org.apache.wicket</groupId>
    <artifactId>wicket-core</artifactId>
    <version>6.21.0</version>
</dependency>

下載：

 * Source: http://www.apache.org/dyn/closer.cgi/wicket/6.21.0  
 * Binary: http://www.apache.org/dyn/closer.cgi/wicket/6.21.0/binaries  

改進列表
=====================

** Bug 修復

    * [WICKET-5882] - AutoComplete suggestion list disappear when I
click on autoComplete scrollbar in IE
    * [WICKET-5898] - StackOverflowError after form submit with a
validation error
    * [WICKET-5925] - wicket-examples DataTablePage is broken
    * [WICKET-5927] - Velocity remote code execution
    * [WICKET-5939] - AjaxEventBehavior should not lower-case the event name
    * [WICKET-5941] - Headers not rendered for components inside
TransparentWebMarkupContainer on ajax update
    * [WICKET-5944] - CSRF prevention does not work with https URLs on
the default port
    * [WICKET-5946] - JavaScript/Css PackageResource should use the
same charset for compressing
    * [WICKET-5959] - HTML input placeholder text breaks
AutoCompleteTextField in IE11
    * [WICKET-5960] - Page header isn't rendered for pages where URL
has changed during render
    * [WICKET-5968] - CachingResourceLocator lookup key doesn't take
strict into account
    * [WICKET-5970] - UrlRenderer does not render fragments
    * [WICKET-5973] - IllegalArgumentException 'bytes' cannot be
negative. on opening Inspector
    * [WICKET-5978] - LazyInitProxyFactory fills permgen space
    * [WICKET-5989] - BaseWicketTester#startComponentInPage fails for
pages with <wicket:header-items></wicket:header> placeholder
    * [WICKET-5994] - Mounted TemplateResourceReference throws
org.apache.wicket.WicketRuntimeException when https is used
    * [WICKET-5996] - Mounted packages throw IllegalArgumentException
when visiting base package url.
    * [WICKET-6005] - WicketRuntimeException from
AjaxPagingNavigator#onAjaxEvent

** 改進

    * [WICKET-5926] - Arquillian Support with Container ServletContext
in BaseWicketTester/WicketTester.
    * [WICKET-5930] - Upgrade Atmosphere to 2.2.7
    * [WICKET-5932] - Allow empty column list for DataTable
    * [WICKET-5933] - Avoid serialization of untouched page after ajax request
    * [WICKET-5935] - IoC Guice: cache proxies and fail on creation
when binding is missing
    * [WICKET-5945] - add a new topic/listener that notifies of Ajax calls done
    * [WICKET-5948] - wicket-ajax.js probably doesn't traverse the
children of <div> or <span>
    * [WICKET-5955] - error from WebPage # reportMissingHead
    * [WICKET-5974] - Change AjaxPagingNavigator#onAjaxEvent() to only
consider parent components that have setOutputMarkupId(true)
    * [WICKET-5976] - Improve the documentation of FeedbackMessages
first(int level)
    * [WICKET-5986] - NumberTextField<N> should use Models for
minimum, maximum and step

** 任務

    * [WICKET-5951] - Upgrade Atmosphere to 2.2.8

Wicket是一個Java 語言的Web開發框架，與Struts，WebWork，Tapestry 相類似。其特點在于對Html和代碼進行了有效的分離（有利于程序員和美工的合作），基于規則的配置(減少了XML 等配置文件的使用)，學習曲線較低（開發方式與C/S相似），更加易于調試（錯誤類型比較少，而且容易定位）。