diff --git a/doc/arm/requirements.txt b/doc/arm/requirements.txt
index 811c3d9493..8d9d05ffb0 100644
--- a/doc/arm/requirements.txt
+++ b/doc/arm/requirements.txt
@@ -1,3 +1,3 @@
-Sphinx==9.1.0
+Sphinx==9.0.4
 docutils==0.22.4
 sphinx_rtd_theme==3.1.0