Are the reports embedded in your application or do you have Birt installed in Tomcat and just call the urls from your application?
In order to update your BIRT Installation, follow this steps:
1.Close Eclipse.
2.In your Eclipse plugins directory, delete all directories that start with "org.eclipse.birt".
3.Install the new BIRT version.
4.Restart Eclipse with the -clean option: eclipse -clean
If you have BIRT installed in Tomcat, you need to undeploy it, then install the new version. Here is the link with the install steps.