I just saw the announcement that Grails v. 1.3.4 has been released. The ChangeLog lists two new features, 10 improvements, and a lot of bug fixes. The Release Notes indicate that Grails 1.3.4 includes Groovy 1.7.4 now.
Binaries and Documentation downloads are available at the CodeHaus Grails.org site, too. Congratulations on the release to the Grails team!