diff --git a/utf64/py/dev_requirements.txt b/utf64/py/dev_requirements.txt
index bc69427..dad5bbf 100644
--- a/utf64/py/dev_requirements.txt
+++ b/utf64/py/dev_requirements.txt
@@ -1,2 +1,2 @@
 black==26.5.1
-flit==3.12.0
+flit==4.0.2