diff --git a/docs/index.html b/docs/index.html
index 650e54e33..8e0dddd7c 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -8,9 +8,8 @@
     <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
             integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
             crossorigin="anonymous"></script>
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/2.11.6/umd/popper.min.js" 
-        integrity="sha512-6UofPqm0QupIL0kzS/UIzekR73/luZdC6i/kXDbWnLOJoqwklBK6519iUnShaYceJ0y4FaiPtX/hRnV/X/xlUQ==" 
-        crossorigin="anonymous"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"
+            integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
     <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
             integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
             crossorigin="anonymous"></script>