diff --git a/prereqs/pips/app_requirements.txt b/prereqs/pips/app_requirements.txt
index c70e7a01f5..611b4cb067 100644
--- a/prereqs/pips/app_requirements.txt
+++ b/prereqs/pips/app_requirements.txt
@@ -11,7 +11,7 @@ beautifulsoup4==4.13.3
 colorama==0.4.6
 Cython==3.0.12
 filelock==3.17.0
-grako==3.16.5
+grako==3.99.9
 html2text==2024.2.26
 ihm==2.2
 imagecodecs==2024.6.1