# My Web Application Bundle stopped working when I moved to Virgo 3.x. What happened?

Virgo Server for Apache Tomcat 3.0 conforms more strictly to the OSGi web applications specification and does not apply default values to some of the manifest headers of a WAB like it used to in Virgo 2.x.

You can easily check whether this is the problem as follows.

As a migration aid, which may be removed in future releases, the previous behaviour may be re-instated by configuring the Web Integration Layer to set WABHeaders=defaulted in $SERVER_HOME/repository/ext/org.eclipse.virgo.web.properties. Please note there is a known issue with certain WAR files which may be worked around using this migration aid.