This is the culmination of years of work.
We have been on Django 1.6 since Review Board 2.0. We've been stuck on

it largely due to Django 1.7's introduction of formal database migration

support, which was incompatible with our own Django Evolution. Solving

this incompatibility was a substantial effort, not just in Django

Evolution but across Djblets, Review Board, and related models, with

many large rewrites across all modules.
Now that we've solved all of this, we're finally ready to bump our

dependency to Django 1.11. This will allow us to switch to more modern

versions of other dependencies in time, and will also enable Python 3

support (though we're still categorizing this support as experimental

for now).
It's worth pointing out that Django 3.0 is the latest version, but

starting at 2.0 they dropped Python 2 support. We still require this for

Review Board 4.0, which is why we've only gone as far as Django 1.11.

Installed a new development environment and ran unit tests on both

Python 2.7 and 3.5-3.7.