We are happy to announce the release of Qt Creator 4.0 RC1 !
I'd like to refer you to the beta blog post for an overview of the new features coming in the 4.0 release. Since then we have been fixing bugs busily, and we believe that what we have now is very near to what we can release as the final 4.0 release soon.
Our icons and the new "Flat" theme also received a lot of polish, and "Flat" is now the default theme for everyone who hasn't ever changed the theme in Qt Creator. The old theme is also still available as "Classic" in Tools > Options > Environment > Interface.