diff --git a/docs/developer-setup.rst b/docs/developer-setup.rst
--- a/docs/developer-setup.rst
+++ b/docs/developer-setup.rst
@@ -94,6 +94,10 @@
     (swh) ~/swh-environment$ pip install pre-commit
     (swh) ~/swh-environment$ ./bin/update
 
+Use the same mypy version our tox containers use:
+
+    (swh) ~/swh-environment$ pip install mypy==0.920
+
 In the future you can re-activate the created virtualenv with::
 
    $ workon swh