Comment 1 for bug 1964987

feature freeze exceptions are for introducing new features into the development release of Ubuntu after feature freeze. This appears to be a request for an update to tomcat9 in focal.

You either need to use the SRU process https://wiki.ubuntu.com/StableReleaseUpdates or, if this is only about security fixes, coordinate with the Ubuntu Security team. However, it seems likely that any security fixes you're concerned about were included in https://launchpad.net/ubuntu/+source/tomcat9/9.0.31-1ubuntu0.2