diff --git a/doc/ext/feature_matrix.py b/doc/ext/feature_matrix.py
index caeaecfad8c1..3d49db973979 100644
--- a/doc/ext/feature_matrix.py
+++ b/doc/ext/feature_matrix.py
@@ -575,7 +575,7 @@ class FeatureMatrixDirective(rst.Directive):
 
 def setup(app):
     app.add_directive('feature_matrix', FeatureMatrixDirective)
-    app.add_stylesheet('feature-matrix.css')
+    app.add_css_file('feature-matrix.css')
     return {
         'parallel_read_safe': True,
         'parallel_write_safe': True,