diff --git a/pdoc/templates/mermaid.html.jinja2 b/pdoc/templates/mermaid.html.jinja2
index dc61c3c6..593cd227 100755
--- a/pdoc/templates/mermaid.html.jinja2
+++ b/pdoc/templates/mermaid.html.jinja2
@@ -6,7 +6,7 @@
     }
 </style>
 <script type="module" defer>
-    import mermaid from "https://cdn.jsdelivr.net/npm/mermaid@10/dist/mermaid.esm.min.mjs";
+    import mermaid from "https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs";
 
     /* Re-invoke Mermaid when DOM content changes, for example during search. */
     document.addEventListener("DOMContentLoaded", () => {
diff --git a/test/testdata/mermaid_demo.html b/test/testdata/mermaid_demo.html
index 643dc47a..4b7775da 100644
--- a/test/testdata/mermaid_demo.html
+++ b/test/testdata/mermaid_demo.html
@@ -18,7 +18,7 @@
     }
 </style>
 <script type="module" defer>
-    import mermaid from "https://cdn.jsdelivr.net/npm/mermaid@10/dist/mermaid.esm.min.mjs";
+    import mermaid from "https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs";
 
     /* Re-invoke Mermaid when DOM content changes, for example during search. */
     document.addEventListener("DOMContentLoaded", () => {