diff --git a/python_modules/libraries/dagstermill/dev-requirements.txt b/python_modules/libraries/dagstermill/dev-requirements.txt
index ab25a047f..d76248a7e 100644
--- a/python_modules/libraries/dagstermill/dev-requirements.txt
+++ b/python_modules/libraries/dagstermill/dev-requirements.txt
@@ -1,2 +1,4 @@
 matplotlib
-scikit-learn>=0.19.0
\ No newline at end of file
+scikit-learn>=0.19.0
+# unpin until https://github.com/jupyter/nbformat/issues/196 is resolved.
+nbformat==5.0.8
\ No newline at end of file