diff --git a/docs/docsite/rst/collections/all_plugins.rst b/docs/docsite/rst/collections/all_plugins.rst
index 35232f7db6..cbe6a9c723 100644
--- a/docs/docsite/rst/collections/all_plugins.rst
+++ b/docs/docsite/rst/collections/all_plugins.rst
@@ -9,3 +9,4 @@ Indexes of all modules and plugins
    :glob:
 
    index_*
+   deprecations
diff --git a/tests/constraints.in b/tests/constraints.in
index 9cf923b204..4a00284273 100644
--- a/tests/constraints.in
+++ b/tests/constraints.in
@@ -3,7 +3,7 @@
 # This constraint file also pins other versions for which there are known limitations.
 
 sphinx == 7.2.5
-antsibull-docs == 2.20.0  # currently approved version
+antsibull-docs == 2.21.0  # currently approved version
 
 sphinx-rtd-theme >= 2.0.0  # Fix 404 pages with new sphinx -- https://github.com/ansible/ansible-documentation/issues/678
 rstcheck < 6  # rstcheck 6.x has problem with rstcheck.core triggered by include files w/ sphinx directives https://github.com/rstcheck/rstcheck-core/issues/3
diff --git a/tests/requirements.txt b/tests/requirements.txt
index d055993ff1..c2e3bd85b2 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -26,7 +26,7 @@ antsibull-changelog==0.34.0
     # via antsibull-docs
 antsibull-core==3.4.0
     # via antsibull-docs
-antsibull-docs==2.20.0
+antsibull-docs==2.21.0
     # via
     #   -c tests/constraints.in
     #   -r tests/requirements.in