diff --git a/pollen_py/pyproject.toml b/pollen_py/pyproject.toml
index 037807f3..f38ca7f6 100644
--- a/pollen_py/pyproject.toml
+++ b/pollen_py/pyproject.toml
@@ -1,6 +1,6 @@
 [build-system]
-requires = ["flit"]
-build-backend = "flit.buildapi"
+requires = ["flit_core >=2,<4"]
+build-backend = "flit_core.buildapi"
 
 [tool.flit.metadata]
 module = "pollen"
@@ -12,4 +12,4 @@ requires-python = ">=3.8"
 requires = []
 
 [tool.flit.scripts]
-exine = "pollen.main:main"
\ No newline at end of file
+exine = "pollen.main:main"