diff --git a/docs/conf.py b/docs/conf.py
index c32af9c03..2d614969d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -41,7 +41,7 @@
     "sphinx.ext.todo",
     "sphinx.ext.coverage",
     "rfc",
-    "m2r",
+    "m2r2",
     "sphinx_rtd_theme",
 ]
 
diff --git a/tox.ini b/tox.ini
index 117a5e901..8b3bdd60c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -72,9 +72,9 @@ commands =
     livedocs: make livehtml
 deps =
     Jinja2<3.1
-    sphinx<3
+    Sphinx==4.5.0
     oauthlib>=3.1.0
-    m2r>=0.2.1
+    m2r2==0.3.2
     mistune<2
     sphinx-rtd-theme
     livedocs: sphinx-autobuild