diff --git a/pyproject.toml b/pyproject.toml
index 990b513..763af1c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ classifiers = [
 ]
 requires-python = ">=3.10"
 dependencies = [
-    "flit-core~=3.12",
+    "flit-core>=3.12,<5.0",
 ]
 
 [project.optional-dependencies]