diff --git a/requirements-sphinx.txt b/requirements-sphinx.txt
index 995d297e..113fa0b7 100644
--- a/requirements-sphinx.txt
+++ b/requirements-sphinx.txt
@@ -11,5 +11,6 @@ typing>=3.5,<=3.5.1
 yapsy==1.11.223
 
 # for sphinx doc only:
+sphinx<1.7
 sphinx-argparse<=0.1.15
 sphinxcontrib-napoleon>=0.2.6,<=0.5.0