diff --git a/changelog/4912.trivial.rst b/changelog/4912.trivial.rst
new file mode 100644
index 000000000..9c5ca6d8e
--- /dev/null
+++ b/changelog/4912.trivial.rst
@@ -0,0 +1 @@
+Remove deprecated Sphinx directive, ``add_description_unit()``.
diff --git a/doc/en/conf.py b/doc/en/conf.py
index 74a43596e..5daa15a06 100644
--- a/doc/en/conf.py
+++ b/doc/en/conf.py
@@ -335,7 +335,7 @@ intersphinx_mapping = {"python": ("https://docs.python.org/3", None)}
 def setup(app):
     # from sphinx.ext.autodoc import cut_lines
     # app.connect('autodoc-process-docstring', cut_lines(4, what=['module']))
-    app.add_description_unit(
+    app.add_object_type(
         "confval",
         "confval",
         objname="configuration value",