diff --git a/python_docs_theme/__init__.py b/python_docs_theme/__init__.py
index 0ee7d25..295c1c5 100644
--- a/python_docs_theme/__init__.py
+++ b/python_docs_theme/__init__.py
@@ -53,6 +53,8 @@ def _html_page_context(
 
 
 def setup(app):
+    app.require_sphinx("3.4")
+
     current_dir = os.path.abspath(os.path.dirname(__file__))
     app.add_html_theme("python_docs_theme", current_dir)