diff --git a/docs/requirements.txt b/docs/requirements.txt
index 536eb946..0b332099 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,4 @@
-sphinx>=1.3,<6.0
+sphinx>=1.3,<9.0
 sphinx-py3doc-enhanced-theme
 sphinxcontrib-plantuml
 setuptools_scm