diff --git a/pyproject.toml b/pyproject.toml
index 18baf08..69a8c3b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "hatchling.build"
 name = "function"
 description = 'A composition function'
 readme = "README.md"
-requires-python = ">=3.11"
+requires-python = ">=3.11,<3.13"
 license = "Apache-2.0"
 keywords = []
 authors = [{ name = "Crossplane Maintainers", email = "info@crossplane.io" }]
@@ -14,6 +14,7 @@ classifiers = [
   "Development Status :: 4 - Beta",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
 ]
 
 dependencies = [
@@ -66,6 +67,8 @@ unit = "python -m unittest tests/*.py"
 [tool.ruff]
 target-version = "py311"
 exclude = ["function/proto/*"]
+
+[tool.ruff.lint]
 select = [
   "A",
   "ARG",
@@ -101,7 +104,7 @@ ignore = ["ISC001"] # Ruff warns this is incompatible with ruff format.
 [tool.ruff.lint.per-file-ignores]
 "tests/*" = ["D"] # Don't require docstrings for tests.
 
-[tool.ruff.isort]
+[tool.ruff.lint.isort]
 known-first-party = ["function"]
 
 [tool.ruff.lint.pydocstyle]