diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 1fbb688..4f2d813 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -85,7 +85,7 @@ jobs:
       - name: build package
         run: python -m build --sdist --wheel . -o dist
       - name: publish to PyPI
-        uses: pypa/gh-action-pypi-publish@v1.6.4
+        uses: pypa/gh-action-pypi-publish@v1.8.5
         with:
           skip_existing: true
           user: __token__
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8429cc3..15f96f8 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -25,7 +25,7 @@ repos:
     hooks:
       - id: isort
   - repo: https://github.com/psf/black
-    rev: 23.1.0
+    rev: 23.3.0
     hooks:
       - id: black
         args: [ --safe ]
@@ -33,22 +33,30 @@ repos:
     rev: 1.13.0
     hooks:
       - id: blacken-docs
-        additional_dependencies: [ black==23.1 ]
+        additional_dependencies: [ black==23.3 ]
   - repo: https://github.com/tox-dev/tox-ini-fmt
-    rev: "0.6.1"
+    rev: "1.3.0"
     hooks:
       - id: tox-ini-fmt
         args: [ "-p", "fix" ]
+  - repo: https://github.com/tox-dev/pyproject-fmt
+    rev: "0.9.2"
+    hooks:
+      - id: pyproject-fmt
   - repo: https://github.com/PyCQA/flake8
     rev: 6.0.0
     hooks:
       - id: flake8
         additional_dependencies:
-          - flake8-bugbear==23.1.20
-          - flake8-comprehensions==3.10.1
-          - flake8-pytest-style==1.7
+          - flake8-bugbear==23.3.23
+          - flake8-comprehensions==3.12
+          - flake8-pytest-style==1.7.2
           - flake8-spellcheck==0.28
           - flake8-unused-arguments==0.0.13
-          - flake8-noqa==1.3
+          - flake8-noqa==1.3.1
           - pep8-naming==0.13.3
-          - flake8-pyproject==1.2.2
+          - flake8-pyproject==1.2.3
+  - repo: https://github.com/tox-dev/pyproject-fmt
+    rev: "0.9.2"
+    hooks:
+    - id: pyproject-fmt
diff --git a/README.md b/README.md
index b2a3cf6..09a8812 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Apply a consistent format to `pyproject.toml` files.
 
 ```yaml
 - repo: https://github.com/tox-dev/pyproject-fmt
-  rev: "0.9.0"
+  rev: "0.9.2"
   hooks:
     - id: pyproject-fmt
 ```
diff --git a/pyproject.toml b/pyproject.toml
index 8aa05be..bdbfb6a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,11 +2,11 @@
 build-backend = "hatchling.build"
 requires = [
   "hatch-vcs>=0.3",
-  "hatchling>=1.13",
+  "hatchling>=1.14",
 ]
 
 [project]
-name = "pyproject_fmt"
+name = "pyproject-fmt"
 description = "Format your pyproject.toml file"
 readme = "README.md"
 keywords = [
@@ -31,27 +31,28 @@ dynamic = [
   "version",
 ]
 dependencies = [
-  "packaging>=23",
-  "tomlkit>=0.11.6",
-  'typing-extensions>=4.4; python_version < "3.8"',
+  "natsort>=8.3.1",
+  "packaging>=23.1",
+  "tomlkit>=0.11.7",
+  'typing-extensions>=4.5; python_version < "3.8"',
 ]
 optional-dependencies.docs = [
-  "furo>=2022.12.7",
+  "furo>=2023.3.27",
   "sphinx>=6.1.3",
   "sphinx-argparse-cli>=1.11",
-  "sphinx-autodoc-typehints!=1.23.4,>=1.22",
-  "sphinx-copybutton>=0.5.1",
+  "sphinx-autodoc-typehints!=1.23.4,>=1.23",
+  "sphinx-copybutton>=0.5.2",
 ]
 optional-dependencies.test = [
-  "covdefaults>=2.2.2",
-  "pytest>=7.2.1",
+  "covdefaults>=2.3",
+  "pytest>=7.3.1",
   "pytest-cov>=4",
   "pytest-mock>=3.10",
 ]
 urls."Bug Tracker" = "https://github.com/tox-dev/pyproject-fmt/issues"
+urls."Changelog" = "https://github.com/tox-dev/pyproject-fmt/releases"
 urls.Documentation = "https://github.com/tox-dev/pyproject-fmt/"
 urls."Source Code" = "https://github.com/tox-dev/pyproject-fmt"
-urls."Changelog" = "https://github.com/tox-dev/pyproject-fmt/releases"
 scripts.pyproject-fmt = "pyproject_fmt.__main__:run"
 
 [tool.hatch]
diff --git a/src/pyproject_fmt/formatter/project.py b/src/pyproject_fmt/formatter/project.py
index bcefd5d..5d3dfa0 100644
--- a/src/pyproject_fmt/formatter/project.py
+++ b/src/pyproject_fmt/formatter/project.py
@@ -25,6 +25,7 @@ def fmt_project(parsed: TOMLDocument, conf: Config) -> None:
 
     sorted_array(cast(Optional[Array], project.get("keywords")), indent=conf.indent)
     sorted_array(cast(Optional[Array], project.get("dynamic")), indent=conf.indent)
+    sorted_array(cast(Optional[Array], project.get("classifiers")), indent=conf.indent, custom_sort="natsort")
 
     normalize_pep508_array(cast(Optional[Array], project.get("dependencies")), conf.indent)
     if "optional-dependencies" in project:
diff --git a/src/pyproject_fmt/formatter/util.py b/src/pyproject_fmt/formatter/util.py
index 32383f5..1216b77 100644
--- a/src/pyproject_fmt/formatter/util.py
+++ b/src/pyproject_fmt/formatter/util.py
@@ -3,8 +3,9 @@
 import sys
 from collections import defaultdict
 from dataclasses import dataclass, field
-from typing import Any, Callable, Sequence
+from typing import Any, Callable, Iterable, Sequence, TypeVar
 
+from natsort import natsorted
 from tomlkit.container import OutOfOrderTableProxy
 from tomlkit.items import (
     AbstractTable,
@@ -36,6 +37,14 @@ def __gt__(self, __other: Any) -> bool:  # noqa: U101
         ...
 
 
+T = TypeVar("T")
+
+
+class SortingFunction(Protocol[T]):
+    def __call__(self, __seq: Iterable[T], key: Callable[[T], SupportsDunderLT]) -> list[T]:  # noqa: U100, U101
+        ...
+
+
 def sort_inline_table(item: tuple[str, Any | Table]) -> str:
     key, value = item
     return f"{key}{'-'.join(value) if isinstance(value, Table) else ''}"
@@ -75,7 +84,10 @@ class ArrayEntries:
 
 
 def sorted_array(
-    array: Array | None, indent: int, key: Callable[[ArrayEntries], str] = lambda e: str(e.text).lower()
+    array: Array | None,
+    indent: int,
+    key: Callable[[ArrayEntries], str] = lambda e: str(e.text).lower(),
+    custom_sort: str | None = None,
 ) -> None:
     if array is None:
         return
@@ -94,7 +106,12 @@ def sorted_array(
     indent_text = " " * indent
     for start_entry in start:
         body.append(_ArrayItemGroup(indent=Whitespace(f"\n{indent_text}"), comment=start_entry))
-    for element in sorted(entries, key=key):
+    sort_method: SortingFunction[ArrayEntries]
+    if custom_sort == "natsort":
+        sort_method = natsorted
+    else:
+        sort_method = sorted  # type: ignore[assignment]
+    for element in sort_method(entries, key=key):
         if element.comments:
             com = " ".join(i.trivia.comment[1:].strip() for i in element.comments)
             comment = Comment(Trivia(comment=f" # {com}", trail=""))
@@ -108,12 +125,12 @@ def sorted_array(
 
 
 def ensure_newline_at_end(body: Table) -> None:
-    content = body
+    content: Table = body
     while True:
         if isinstance(content, AoT) and content.value and isinstance(content[-1], (AoT, Table)):
             content = content[-1]
         elif isinstance(content, Table) and content.value.body and isinstance(content.value.body[-1][1], (AoT, Table)):
-            content = content.value.body[-1][1]
+            content = content.value.body[-1][1]  # type: ignore # can be AoT temporarily
         else:  # pragma: no cover
             # coverage has a bug on python < 3.10, seeing this line as uncovered
             # https://github.com/nedbat/coveragepy/issues/1480
diff --git a/tests/formatter/test_project.py b/tests/formatter/test_project.py
index 5e3e97c..9a36d8f 100644
--- a/tests/formatter/test_project.py
+++ b/tests/formatter/test_project.py
@@ -18,6 +18,40 @@ def test_project_name(fmt: Fmt, value: str) -> None:
     fmt(fmt_project, value, '[project]\nname="a-b"\n')
 
 
+def test_project_classifiers(fmt: Fmt) -> None:
+    start = """
+    [project]
+    classifiers = [
+      "Operating System :: OS Independent",
+      "Programming Language :: Python",
+      "Programming Language :: Python :: 3.10",
+      "Programming Language :: Python :: 3 :: Only",
+      "License :: OSI Approved :: MIT License",
+      "Programming Language :: Python :: 3.7",
+      "Programming Language :: Python :: 3.8",
+      "License :: OSI Approved :: MIT License",
+      "Programming Language :: Python :: 3.9",
+      "Programming Language :: Python :: 3.11",
+    ]
+    """
+    expected = """
+    [project]
+    classifiers = [
+      "License :: OSI Approved :: MIT License",
+      "License :: OSI Approved :: MIT License",
+      "Operating System :: OS Independent",
+      "Programming Language :: Python",
+      "Programming Language :: Python :: 3 :: Only",
+      "Programming Language :: Python :: 3.7",
+      "Programming Language :: Python :: 3.8",
+      "Programming Language :: Python :: 3.9",
+      "Programming Language :: Python :: 3.10",
+      "Programming Language :: Python :: 3.11",
+    ]
+    """
+    fmt(fmt_project, start, expected)
+
+
 def test_project_dependencies(fmt: Fmt) -> None:
     start = '[project]\ndependencies=["pytest","pytest-cov",]'
     expected = '[project]\ndependencies=[\n  "pytest",\n  "pytest-cov",\n]\n'
diff --git a/tests/formatter/test_tools.py b/tests/formatter/test_tools.py
index 0497daf..0ef8ec4 100644
--- a/tests/formatter/test_tools.py
+++ b/tests/formatter/test_tools.py
@@ -54,7 +54,6 @@ def test_sub_table_newline(fmt: Fmt) -> None:
     content = """
     [tool.mypy]
     a = 0
-
     [[tool.mypy.overrides]]
     a = 1
     [tool.something-else]
@@ -63,7 +62,6 @@ def test_sub_table_newline(fmt: Fmt) -> None:
     expected = """
     [tool.mypy]
     a = 0
-
     [[tool.mypy.overrides]]
     a = 1
 
diff --git a/tox.ini b/tox.ini
index 070de9e..d6b4c78 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,7 @@
 [tox]
-envlist =
+requires =
+    tox>=4.2
+env_list =
     fix
     py311
     py310
@@ -10,16 +12,17 @@ envlist =
     readme
     docs
 skip_missing_interpreters = true
-requires = tox>=4.2
 
 [testenv]
 description = run the unit tests with pytest under {basepython}
-setenv =
+package = wheel
+wheel_build_env = .pkg
+extras =
+    test
+set_env =
     COVERAGE_FILE = {toxworkdir}/.coverage.{envname}
     COVERAGE_PROCESS_START = {toxinidir}/setup.cfg
     _COVERAGE_SRC = {envsitepackagesdir}/sphinx_argparse_cli
-extras =
-    test
 commands =
     python -m pytest {tty:--color=yes} {posargs: \
       --junitxml {toxworkdir}{/}junit.{envname}.xml --cov {envsitepackagesdir}{/}pyproject_fmt \
@@ -27,26 +30,25 @@ commands =
       --cov-config=pyproject.toml --no-cov-on-fail --cov-report term-missing:skip-covered --cov-context=test \
       --cov-report html:{envtmpdir}{/}htmlcov --cov-report xml:{toxworkdir}{/}coverage.{envname}.xml \
       tests}
-package = wheel
-wheel_build_env = .pkg
 
 [testenv:fix]
 description = run static analysis and style check using flake8
 skip_install = true
 deps =
-    pre-commit>=3.0.4
+    pre-commit>=3.2.2
 commands =
     pre-commit run --all-files --show-diff-on-failure
     python -c 'print("hint: run {envdir}/bin/pre-commit install to add checks as pre-commit hook")'
 
 [testenv:type]
 description = run type check on code base
-setenv =
-    {tty:MYPY_FORCE_COLOR = 1}
 deps =
-    mypy==1
+    mypy==1.2
+set_env =
+    {tty:MYPY_FORCE_COLOR = 1}
 commands =
-    mypy --strict --python-version 3.10 src tests
+    mypy src
+    mypy tests
 
 [testenv:readme]
 description = check that the long description is valid
@@ -68,10 +70,10 @@ commands =
 
 [testenv:dev]
 description = generate a DEV environment
+package = editable
 extras =
     docs
     test
 commands =
     python -m pip list --format=columns
     python -c 'import sys; print(sys.executable)'
-package = editable
diff --git a/whitelist.txt b/whitelist.txt
index e1097a0..8eff61c 100644
--- a/whitelist.txt
+++ b/whitelist.txt
@@ -11,6 +11,8 @@ intersphinx
 iread
 iwrite
 mkfifo
+natsort
+natsorted
 nitpicky
 pep508
 py38