diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 7369d77..e92bff8 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -69,6 +69,7 @@ We use `nox `__ to instrument our tests.
- To test your changes, run unit tests with ``nox``::
+ $ nox -s unit-2.7
$ nox -s unit-3.8
$ ...
@@ -143,6 +144,7 @@ Running System Tests
# Run all system tests
$ nox -s system-3.8
+ $ nox -s system-2.7
# Run a single system test
$ nox -s system-3.8 -- -k
@@ -150,8 +152,9 @@ Running System Tests
.. note::
- System tests are only configured to run under Python 3.8.
- For expediency, we do not run them in older versions of Python 3.
+ System tests are only configured to run under Python 2.7 and
+ Python 3.8. For expediency, we do not run them in older versions
+ of Python 3.
This alone will not run the tests. You'll need to change some local
auth settings and change some configuration in your project to