Review Board 1.5.5 is out, which is a pretty standard bug fix release with a variety of fixes here and there, plus a new and convenient link on the Add/Change Repository pages to show the current SSH key.
There are some good fixes for crashes that could happen in rare occasions in the diff viewer and admin UIs, fixes to image fetching in HTML e-mails, fixes for conflicting change numbers across multiple Perforce repositories, and more.
One real important fix, which is the main reason for tonight's release, is that one of our dependencies, python-dateutil, recently released a new version that was only compatible with Python 3. Due to Review Board requesting the latest and greatest, we'd attempt to install it, which would cause problems. If you've recently tried installing Review Board (just over the past couple of days) and have hit strange errors, try finding and removing your python_dateutil directory and install Review Board 1.5.5.
Release notes are available with the complete list of fixes.