diff --git a/docs/conf.py b/docs/conf.py
index f0b5683..a1cf646 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -72,7 +72,7 @@
     "sphinx_sitemap",
     "sphinxcontrib.httpdomain",  # plone.restapi
     "sphinxcontrib.httpexample",  # plone.restapi
-    # "sphinxcontrib.mermaid",
+    "sphinxcontrib.mermaid",
     "sphinxcontrib.video",
     "sphinxext.opengraph",
 ]
@@ -358,7 +358,7 @@
 
 
 # -- Mermaid configuration ----------------------------------
-# mermaid_version = "10.9.1"
+mermaid_version = "11.2.0"
 
 
 # -- OpenGraph configuration ----------------------------------
diff --git a/docs/reference/extensions.md b/docs/reference/extensions.md
index 58e9623..2c95ae8 100644
--- a/docs/reference/extensions.md
+++ b/docs/reference/extensions.md
@@ -52,6 +52,6 @@ These extensions are built in and can be activated by respective entries in the
 -   [`sphinxcontrib.httpexample`](https://sphinxcontrib-httpexample.readthedocs.io/en/latest/) enhances `sphinxcontrib-httpdomain` by generating RESTful HTTP API call examples for different tools from a single HTTP request example.
     Supported tools include [`curl`](https://curl.se/), [`wget`](https://www.gnu.org/software/wget/), [`httpie`](https://httpie.io/), and [`python-requests`](https://requests.readthedocs.io/en/latest/).
     It's used by Plone's {doc}`plone:plone.restapi/docs/source/index`.
-% -   [`sphinxcontrib.mermaid`](https://pypi.org/project/sphinxcontrib-mermaid/) allows you to embed [Mermaid](https://mermaid.js.org/) graphs in your documents, including general flowcharts, sequence diagrams, and Gantt charts.
+-   [`sphinxcontrib.mermaid`](https://pypi.org/project/sphinxcontrib-mermaid/) allows you to embed [Mermaid](https://mermaid.js.org/) graphs in your documents, including general flowcharts, sequence diagrams, and Gantt charts.
 -   [`sphinxcontrib.video`](https://pypi.org/project/sphinxcontrib-video/) allows you to embed local videos as defined by the HTML5 standard.
 -   [`sphinxext.opengraph`](https://pypi.org/project/sphinxext-opengraph/) generates [OpenGraph metadata](https://ogp.me/).
diff --git a/news/38.feature b/news/38.feature
new file mode 100644
index 0000000..67a0062
--- /dev/null
+++ b/news/38.feature
@@ -0,0 +1 @@
+Restore support for Mermaid. @stevepiercy
diff --git a/pyproject.toml b/pyproject.toml
index 39bceaf..7a08768 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ docs = [
   "sphinx-copybutton",
   "sphinx-design",
   "sphinx-examples",
-#  "sphinxcontrib-mermaid==0.9.2",  # See https://github.com/mgaitan/sphinxcontrib-mermaid/issues/137
+  "sphinxcontrib-mermaid",
   "sphinx-notfound-page",
   "sphinx-reredirects",
   "sphinx-sitemap",
diff --git a/requirements-dev.txt b/requirements-dev.txt
index d8bd5dc..f0c55a6 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -127,7 +127,9 @@ pyproject-metadata==0.9.0
 pyroma==4.2
     # via zest-releaser
 pyyaml==6.0.2
-    # via myst-parser
+    # via
+    #   myst-parser
+    #   sphinxcontrib-mermaid
 readme-renderer==44.0
     # via
     #   twine
@@ -147,7 +149,7 @@ rich==13.9.4
     # via
     #   sphinx-theme-builder
     #   twine
-setuptools==75.4.0
+setuptools==75.5.0
     # via
     #   check-manifest
     #   pyroma
@@ -179,6 +181,7 @@ sphinx==7.4.7
     #   sphinx-sitemap
     #   sphinxcontrib-httpdomain
     #   sphinxcontrib-httpexample
+    #   sphinxcontrib-mermaid
     #   sphinxcontrib-video
     #   sphinxext-opengraph
 sphinx-autobuild==2024.10.3
@@ -217,6 +220,8 @@ sphinxcontrib-httpexample==1.3
     # via plone-sphinx-theme (pyproject.toml)
 sphinxcontrib-jsmath==1.0.1
     # via sphinx
+sphinxcontrib-mermaid==1.0.0
+    # via plone-sphinx-theme (pyproject.toml)
 sphinxcontrib-qthelp==2.0.0
     # via sphinx
 sphinxcontrib-serializinghtml==2.0.0
@@ -249,7 +254,7 @@ vale==3.9.0.0
     # via plone-sphinx-theme (pyproject.toml)
 watchfiles==0.24.0
     # via sphinx-autobuild
-websockets==14.0
+websockets==14.1
     # via sphinx-autobuild
 wheel==0.45.0
     # via
diff --git a/requirements-docs.txt b/requirements-docs.txt
index 3dd7b44..bc287b0 100644
--- a/requirements-docs.txt
+++ b/requirements-docs.txt
@@ -68,7 +68,9 @@ pygments==2.18.0
     #   pydata-sphinx-theme
     #   sphinx
 pyyaml==6.0.2
-    # via myst-parser
+    # via
+    #   myst-parser
+    #   sphinxcontrib-mermaid
 requests==2.32.3
     # via sphinx
 six==1.16.0
@@ -96,6 +98,7 @@ sphinx==7.4.7
     #   sphinx-sitemap
     #   sphinxcontrib-httpdomain
     #   sphinxcontrib-httpexample
+    #   sphinxcontrib-mermaid
     #   sphinxcontrib-video
     #   sphinxext-opengraph
 sphinx-autobuild==2024.10.3
@@ -130,6 +133,8 @@ sphinxcontrib-httpexample==1.3
     # via plone-sphinx-theme (pyproject.toml)
 sphinxcontrib-jsmath==1.0.1
     # via sphinx
+sphinxcontrib-mermaid==1.0.0
+    # via plone-sphinx-theme (pyproject.toml)
 sphinxcontrib-qthelp==2.0.0
     # via sphinx
 sphinxcontrib-serializinghtml==2.0.0
@@ -150,7 +155,7 @@ uvicorn==0.32.0
     # via sphinx-autobuild
 watchfiles==0.24.0
     # via sphinx-autobuild
-websockets==14.0
+websockets==14.1
     # via sphinx-autobuild
 wheel==0.45.0
     # via astunparse
diff --git a/src/plone_sphinx_theme/__init__.py b/src/plone_sphinx_theme/__init__.py
index 2dcabd1..551b526 100644
--- a/src/plone_sphinx_theme/__init__.py
+++ b/src/plone_sphinx_theme/__init__.py
@@ -1,5 +1,5 @@
 """
-A Twitter Bootstrap-based Sphinx theme for documentation of Plone packages and projects, inheriting from Sphinx Book Theme and PyData Sphinx Theme.
+A Bootstrap-based Sphinx theme for documentation of Plone packages and projects, inheriting from Sphinx Book Theme and PyData Sphinx Theme.
 """
 import os
 from pathlib import Path