Migration of Web applications deployed in previous versions of WebSphere® Application Server is usually not necessary. Versions 2.2 and 2.3 of the Java Servlet specification and versions 1.2 and 1.4 of the JavaServer Pages (JSP) specifications are still supported unless the behavior was changed in the Servlet 2.4 or JSP 2.0 specifications. Version 2.4 of the Java Servlet specification and version 2.0 of the JSP specification are still supported unless the behavior was changed in the Servlet 2.5 or JSP 2.1 Specification. These changes are generally available in more detail in their corresponding specification.