diff --git a/AGENTS.md b/AGENTS.md
index ecac93d..49e5b3f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -80,7 +80,7 @@ NUMBA_CACHE_DIR=/tmp/numba_cache MPLCONFIGDIR=/tmp/matplotlib python -m pytest t
 
 PRs must pass `pytest --cov` on the CI matrix (Python 3.12 **and** 3.13). There
 is no black/ruff/flake8 gate — formatting is advisory. (`requires-python` in
-`pyproject.toml` is `>=3.9`.)
+`pyproject.toml` is `>=3.12`.)
 
 ## Public API
 
diff --git a/autonerves/__init__.py b/autonerves/__init__.py
index 23fce7c..6b2cd8a 100644
--- a/autonerves/__init__.py
+++ b/autonerves/__init__.py
@@ -42,24 +42,32 @@ def _emit_python_version_warning():
         return
 
     py = f"{current[0]}.{current[1]}"
-    lines = [
-        f"PyAuto: Python {py} detected -- first-class support is 3.12 and 3.13.",
-        "",
-        f"Things will probably work fine on {py}, but it is not the recommended",
-        "version and you may hit edge cases.",
-    ]
-    if current < (3, 11):
-        lines.extend(
-            [
-                "",
-                "Note: JAX acceleration is not available on Python <3.11. Models",
-                "that pass use_jax=True will error.",
-            ]
+    if current < (3, 12):
+        lines = [
+            f"PyAuto: Python {py} detected -- Python 3.12 or newer is required.",
+            "",
+            "This Python version is unsupported by current PyAuto releases.",
+            "Install Python 3.12 or 3.13, or pin a pre-migration PyAuto release.",
+        ]
+        warning = (
+            f"PyAuto: running on unsupported Python {py}; current releases "
+            "require Python >=3.12."
+        )
+    else:
+        lines = [
+            f"PyAuto: Python {py} detected -- this Python version is experimental.",
+            "",
+            "PyAuto currently tests and supports Python 3.12 and 3.13.",
+            f"Python {py} may encounter known compatibility issues.",
+            "Use Python 3.12 or 3.13 for production work.",
+        ]
+        warning = (
+            f"PyAuto: running on experimental Python {py}; supported versions "
+            "are 3.12/3.13."
         )
     lines.extend(
         [
             "",
-            "Recommended: install Python 3.12 or 3.13.",
             "To silence this warning, add to <cwd>/config/general.yaml:",
             "",
             "    version:",
@@ -76,9 +84,9 @@ def _emit_python_version_warning():
 
     print("\n".join(framed), file=sys.stderr)
     warnings.warn(
-        f"PyAuto: running on Python {py}; first-class support is 3.12/3.13. "
-        f"Suppress this warning via 'version.python_version_check: False' in "
-        f"config/general.yaml.",
+        warning
+        + " Suppress this warning via 'version.python_version_check: False' "
+        "in config/general.yaml.",
         UserWarning,
         stacklevel=2,
     )
diff --git a/pyproject.toml b/pyproject.toml
index 5396575..2872c81 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ dynamic = ["version"]
 description = "PyAuto Configration"
 readme = { file = "README.md", content-type = "text/markdown" }
 license = { text = "MIT" }
-requires-python = ">=3.9"
+requires-python = ">=3.12"
 authors = [
     { name = "James Nightingale", email = "James.Nightingale@newcastle.ac.uk" },
     { name = "Richard Hayes", email = "richard@rghsoftware.co.uk" },
@@ -18,15 +18,11 @@ classifiers = [
   "Topic :: Scientific/Engineering :: Physics",
   "Natural Language :: English",
   "Operating System :: OS Independent",
-  "Programming Language :: Python :: 3.9",
-  "Programming Language :: Python :: 3.10",
-  "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13"
 ]
 keywords = ["cli"]
 dependencies = [
-    "pathlib",
     "typing-inspect>=0.4.0",
     "PyYAML>=6.0.1",
     "numpy>=1.24.0,<3.0.0"
@@ -47,9 +43,9 @@ local_scheme = "no-local-version"
 
 [project.optional-dependencies]
 jax = [
-    "jax>=0.7.0,<0.11.0; python_version >= '3.11'",
-    "jaxlib>=0.7.0,<0.11.0; python_version >= '3.11'",
-    "jaxnnls==1.0.1; python_version >= '3.11'"
+    "jax>=0.7.0,<0.11.0",
+    "jaxlib>=0.7.0,<0.11.0",
+    "jaxnnls==1.0.1"
 ]
 optional = [
     "autonerves[jax]",
@@ -63,4 +59,4 @@ testpaths = ["test_autonerves"]
 filterwarnings = [
     "ignore:cuda_plugin_extension:UserWarning",
     "ignore::DeprecationWarning:jax",
-]
\ No newline at end of file
+]
diff --git a/test_autonerves/test_python_version.py b/test_autonerves/test_python_version.py
new file mode 100644
index 0000000..e3a3440
--- /dev/null
+++ b/test_autonerves/test_python_version.py
@@ -0,0 +1,78 @@
+import sys
+from types import SimpleNamespace
+import warnings
+
+import pytest
+
+import autonerves
+
+
+def _set_python_version(monkeypatch, major, minor):
+    monkeypatch.setattr(
+        autonerves,
+        "sys",
+        SimpleNamespace(version_info=(major, minor), stderr=sys.stderr),
+    )
+    monkeypatch.setattr(
+        autonerves,
+        "_python_version_check_bypassed",
+        lambda: False,
+    )
+
+
+@pytest.mark.parametrize("minor", [12, 13])
+def test_supported_python_versions_do_not_warn(monkeypatch, capsys, minor):
+    _set_python_version(monkeypatch, major=3, minor=minor)
+
+    with warnings.catch_warnings(record=True) as caught:
+        warnings.simplefilter("always")
+        autonerves._emit_python_version_warning()
+
+    assert caught == []
+    assert capsys.readouterr().err == ""
+
+
+def test_python_below_minimum_is_reported_as_unsupported(monkeypatch, capsys):
+    _set_python_version(monkeypatch, major=3, minor=11)
+
+    with pytest.warns(UserWarning, match=r"require Python >=3\.12"):
+        autonerves._emit_python_version_warning()
+
+    message = capsys.readouterr().err
+    assert "Python 3.12 or newer is required" in message
+    assert "unsupported by current PyAuto releases" in message
+    assert "pre-migration PyAuto release" in message
+
+
+def test_python_above_supported_range_is_reported_as_experimental(monkeypatch, capsys):
+    _set_python_version(monkeypatch, major=3, minor=14)
+
+    with pytest.warns(UserWarning, match=r"experimental Python 3\.14"):
+        autonerves._emit_python_version_warning()
+
+    message = capsys.readouterr().err
+    assert "Python 3.14 detected -- this Python version is experimental" in message
+    assert "tests and supports Python 3.12 and 3.13" in message
+    assert "Use Python 3.12 or 3.13 for production work" in message
+
+
+def test_python_version_warning_respects_yaml_bypass(monkeypatch, tmp_path, capsys):
+    config_path = tmp_path / "config"
+    config_path.mkdir()
+    (config_path / "general.yaml").write_text(
+        "version:\n  python_version_check: false\n"
+    )
+    monkeypatch.chdir(tmp_path)
+    monkeypatch.setattr(
+        autonerves,
+        "sys",
+        SimpleNamespace(version_info=(3, 14)),
+    )
+
+    with warnings.catch_warnings(record=True) as caught:
+        warnings.simplefilter("always")
+        autonerves._emit_python_version_warning()
+
+    assert autonerves._python_version_check_bypassed() is True
+    assert caught == []
+    assert capsys.readouterr().err == ""