diff --git a/book/src/requirements.txt b/book/src/requirements.txt
index 0ef75b2f..34512448 100644
--- a/book/src/requirements.txt
+++ b/book/src/requirements.txt
@@ -1,4 +1,4 @@
-black==24.10.0
+black==25.9.0
 coverage==7.10.6
 flake8==7.1.2
 hypothesis==6.139.2