diff --git a/.readthedocs.requirements.txt b/.readthedocs.requirements.txt
index 122610498..1f028de41 100644
--- a/.readthedocs.requirements.txt
+++ b/.readthedocs.requirements.txt
@@ -1 +1 @@
-sphinx<4.4.0
+sphinx==4.4.0
diff --git a/.readthedocs.yaml b/.readthedocs.yml
similarity index 100%
rename from .readthedocs.yaml
rename to .readthedocs.yml
diff --git a/conf.py b/conf.py
index 68d11f0f9..0170a872b 100644
--- a/conf.py
+++ b/conf.py
@@ -138,7 +138,7 @@ generate_tag_indices()
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = '1.8'
+needs_sphinx = '3.4.3'
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom