Review Board 1.7.11 is released. It's a small release that just fixes a visual issue with the drop-down menus on IE9, and a compatibility issue with Python 2.5.
If you're primarily using non-IE browsers, and using something newer than Python 2.5, you don't need to upgrade to 1.7.11.
For those using Python 2.5, we recommend planning an upgrade to Python 2.7 soon. Review Board 1.8 will stop supporting Python 2.5, and 2.7 is your best bet for longer-term compatibility.
Release notes are available.