diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 # Add here external Python modules dependencies, one per line. Module names
 # should match https://pypi.python.org/pypi names. For the full spec or
 # dependency lines, see https://pip.readthedocs.org/en/1.1/requirements.html
-attrs
+attrs != 21.1.0  # https://github.com/python-attrs/attrs/issues/804
 attrs_strict >= 0.0.7
 deprecated
 hypothesis