diff --git a/pyproject.toml b/pyproject.toml
index d1663a7..90243f3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ['flit_core >=3.2,<4']
+requires = ['flit_core >=3.2,<5']
 build-backend = 'flit_core.buildapi'
 
 [project]