The news says that "BIRT 4.2.2 has been officially released. 03/04/13", and I see direct links to the packages, but the update site http://download.eclipse.org/birt/update-site/4.2/ does not seem to have it available yet.
The question is whether it is eventually updated and I just need to wait a little or it is moved to a different URL.
It does not look updated yet. Take a look at: http://wiki.eclipse.org/BIRT_Update_Site_URL
And you will see the 4.2 interim site which does appear to be updated.
Can you open a bugzilla entry for this?