diff --git a/src/Text/Pandoc/Options.hs b/src/Text/Pandoc/Options.hs
index 3705b9c41..261766b08 100644
--- a/src/Text/Pandoc/Options.hs
+++ b/src/Text/Pandoc/Options.hs
@@ -444,7 +444,7 @@ isEnabled :: HasSyntaxExtensions a => Extension -> a -> Bool
 isEnabled ext opts = ext `extensionEnabled` getExtensions opts
 
 defaultMathJaxURL :: Text
-defaultMathJaxURL = "https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml-full.js"
+defaultMathJaxURL = "https://cdn.jsdelivr.net/npm/mathjax@4/tex-chtml.js"
 
 defaultWebTeXURL :: Text
 defaultWebTeXURL = "https://latex.codecogs.com/png.latex?"
diff --git a/test/s5-fancy.html b/test/s5-fancy.html
index f2f54811d..16107033d 100644
--- a/test/s5-fancy.html
+++ b/test/s5-fancy.html
@@ -43,7 +43,7 @@
   <!-- S5 JS -->
   <script src="s5/default/slides.js" type="text/javascript"></script>
   <script defer=""
-  src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml-full.js"
+  src="https://cdn.jsdelivr.net/npm/mathjax@4/tex-chtml.js"
   type="text/javascript"></script>
 </head>
 <body>
