diff --git a/ci/requirements-3.6_DOC.run b/ci/requirements-3.6_DOC.run
index fa9cab32c0ac2..084f38ce17eb2 100644
--- a/ci/requirements-3.6_DOC.run
+++ b/ci/requirements-3.6_DOC.run
@@ -5,7 +5,7 @@ sphinx
 nbconvert
 nbformat
 notebook
-matplotlib=2.1*
+matplotlib
 seaborn
 scipy
 lxml