Review Board 1.7.5 is out. It fixes a few, mostly small problems people have hit, and a major compatibility change with the newly released django-pipeline 1.3.
If you installed 1.7.4 in the past week, you may have had a crash when accessing most pages, possibly saying "CompilerError." This was due to some compatibility changes in django-pipeline 1.3 that we still need to investigate. However, that release also dropped Python 2.5 support, which means we'll be requiring 1.2.24 from here on out. My apologies to any packagers that this affects.
See the release notes for the full list of changes.