Servlet 2.3 not supported by Websphere 4.0 .. solution?

I have got the problem now...
When I create a jar file I get that error
com.ibm.etools.archive.exception.NotSupportedException: Type is unrecognized or not yet supported: PUBLIC_ID=-//Sun Microsystems, Inc.//DTD J2EE Application 1.3//EN;SYSTEM_ID=http://java.sun.com/dtd/application_1_3.dtd
What is happening is that I am trying to deploy a Servlet 2.3 into WebSphere 4.0. Servlet 2.2 spec is supported by websphere.
What is the solution to this? Is there a patch or a jar file I need to add to application server bin directory that will accept my servlets?

You have to move to WAS 5.0 to use Servlet 2.3. There is no patch file to make this work.
Kyle

Hi,
I am using websphere 5.0 and trying to install an EAR file onto the WAS.
It works fine in the Test Env, but when I tried deploy
I am getting the error
"Type is unrecognized or not yet supported: PUBLIC_ID=-//Sun Microsystems, Inc.//DTD J2EE Application 1.3//EN;SYSTEM_ID=http://java.sun.com/dtd/application_1_3.dtd

at com.ibm.etools.j2ee.xml.J2EEXmlDtDEntityResolver.resolveEntity(J2EEXmlDtDEntityResolver.java:46)"
When I used AAT(Application Assembly Tool. Also, When I tried to use the Web admin tool, it says the file is not an EAR file and it throws error "APPW0004E: Application Install or Modify Bindingsaction for the chosen application failed"

I am not sure what I am doing wrong. I just followed the deploy instructions from couple of Websphere books.
Thanks in advance.
Raj