diff --git a/pyproject.toml b/pyproject.toml
index d265ac3..11d66a0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -116,6 +116,9 @@ ignore = [
 channels = ["conda-forge"]
 platforms = ["win-64", "linux-64", "osx-64"]
 
+[tool.pixi.system-requirements]
+macos = "12.0"
+
 [tool.pixi.pypi-dependencies]
 flopy4 = { path = ".", editable = true }