diff --git a/doc/requirements.txt b/doc/requirements.txt
index 44cb208..559dc80 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1,6 +1,6 @@
 # This is required for the docs build jobs
-sphinx>=2.0.0,!=2.1.0 # BSD
+sphinx>=3.5.1 # BSD
 openstackdocstheme>=2.2.1 # Apache-2.0
 
 # This is required for the releasenotes build jobs
 reno>=3.1.0 # Apache-2.0