diff --git a/pyproject.toml b/pyproject.toml
index a463c36..20222da 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@
 
 [build-system]
 build-backend = "flit_core.buildapi"
-requires = ["flit_core >=3.2,<4"]
+requires = ["flit_core >=3.2,<5"]
 
 [project]
 authors = [{name = "Kevin Meagher"}]