diff --git a/pyproject.toml b/pyproject.toml
index ed3d55b8..81ae9b35 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,8 +3,8 @@ line-length = 88
 target-version = ['py36', 'py37', 'py38']
 
 [build-system]
-requires = ["flit"]
-build-backend = "flit.buildapi"
+requires = ["flit_core >=2,<4"]
+build-backend = "flit_core.buildapi"
 
 [tool.flit.metadata]
 module = "fbchat"