diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 9706ae0..d1aabd8 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,25 +13,26 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Python
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v5
       with:
-        python-version: 3.7
-    - uses: pre-commit/action@v2.0.0
+        python-version: '3.10'
+    - uses: pre-commit/action@v3.0.1
+      continue-on-error: true
 
   tests:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ['3.10', '3.11', '3.12', '3.13']
         os: [ubuntu-latest, windows-latest]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -44,16 +45,18 @@ jobs:
 
     - name: Run pytest
       run: |
-        pytest --cov=mdformat_plugin --cov-report=xml --cov-report=term-missing
+        pytest --cov=mdformat_hallmark --cov-report=xml --cov-report=term-missing
 
     - name: Upload to Codecov
-      if: matrix.os == 'ubuntu-latest' && matrix.python-version == 3.7
-      uses: codecov/codecov-action@v1
+      if: matrix.os == 'ubuntu-latest' && matrix.python-version == 3.10
+      uses: codecov/codecov-action@v5.4.2
       with:
-        name: pytests-py3.7
-        flags: pytests
+        name: codecov-umbrella
+        flags: unit
+        env_vars: RUNNER_OS,PYTHON_VERSION
         file: ./coverage.xml
-        fail_ci_if_error: true
+        token: ${{ secrets.CODECOV_TOKEN }}
+        fail_ci_if_error: false
 
   pre-commit-hook:
     runs-on: ubuntu-latest
@@ -61,9 +64,9 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v5
       with:
-        python-version: 3.7
+        python-version: '3.10'
 
     - name: Installation (deps and package)
       run: |
@@ -82,10 +85,10 @@ jobs:
     steps:
     - name: Checkout source
       uses: actions/checkout@v2
-    - name: Set up Python 3.7
-      uses: actions/setup-python@v1
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v5
       with:
-        python-version: 3.7
+        python-version: '3.10'
     - name: install flit
       run: |
         pip install flit~=3.0
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index e481775..7418a8c 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v3.4.0
+  rev: v5.0.0
   hooks:
   - id: end-of-file-fixer
   - id: mixed-line-ending
@@ -8,22 +8,22 @@ repos:
   - id: check-yaml
   - id: check-toml
 - repo: https://github.com/pre-commit/pygrep-hooks
-  rev: v1.8.0
+  rev: v1.10.0
   hooks:
   - id: python-check-blanket-noqa
 - repo: https://github.com/timothycrosley/isort
-  rev: 5.8.0
+  rev: 5.13.2
   hooks:
   - id: isort
 - repo: https://github.com/psf/black
-  rev: 20.8b1
+  rev: 24.10.0
   hooks:
   - id: black
-- repo: https://gitlab.com/pycqa/flake8
-  rev: 3.9.0
+- repo: https://github.com/pycqa/flake8
+  rev: 7.3.0
   hooks:
   - id: flake8
     additional_dependencies:
-    - flake8-bugbear==21.3.2
-    - flake8-builtins==1.5.3
-    - flake8-comprehensions==3.4.0
+    - flake8-bugbear
+    - flake8-builtins
+    - flake8-comprehensions
diff --git a/LICENSE b/LICENSE
index 2a08e1c..292a6fc 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020 Executable Books
+Copyright (c) 2025 Executable Books
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 41054b9..f3ae713 100644
--- a/README.md
+++ b/README.md
@@ -1,23 +1,10 @@
-# mdformat-plugin
+# mdformat-hallmark
 
-[![Build Status][ci-badge]][ci-link]
-[![codecov.io][cov-badge]][cov-link]
-[![PyPI version][pypi-badge]][pypi-link]
+[![Build Status](https://github.com/calgray/mdformat-hallmark/actions/workflows/tests.yml/badge.svg?branch=master)](<https://github.com/calgray/mdformat-hallmark/actions?query=workflow%3ATests+branch%3Amaster+event%3Apush>)
+[![codecov.io](https://codecov.io/gh/calgray/mdformat-hallmark/branch/main/graph/badge.svg)](https://codecov.io/gh/xarray-contrib/astropy-xarray)
+[![PyPI version](https://badge.fury.io/py/mdformat-hallmark.svg)](<https://badge.fury.io/py/mdformat-hallmark>)
 
-An [mdformat](https://github.com/executablebooks/mdformat) plugin for...
-
-## Required changes for a new plugin
-
-This demonstration is setup with a plugin named `plugin`.
-There are a number of locations to change.
-At a top level for a plugin `foo` at least the following changes are required
-
-- Global find and replace `mdformat_plugin` to `mdformat_foo` including folder names.
-- Global find and replace `mdformat-plugin` to `mdformat-foo` including folder names.
-- `tests/test_fixtures.py`: `output = mdformat.text(text, extensions={"plugin"})` becomes `output = mdformat.text(text, extensions={"foo"})`
-- `pyproject.toml` in addition to the global find and replace: `plugin = "mdformat_plugin"` becomes `foo = "mdformat_foo"`
-
-Do not forget to update authorship / maintainers in `pyproject.toml` as well.
+An [mdformat](https://github.com/executablebooks/mdformat) plugin for compatibility with [hallmark](https://github.com/vweevers/hallmark) formatted Markdown and [Common Changelog](https://common-changelog.org/).
 
 ## Development
 
@@ -75,9 +62,9 @@ or trigger the GitHub Action job, by creating a release with a tag equal to the
 
 Note, this requires generating an API key on PyPi and adding it to the repository `Settings/Secrets`, under the name `PYPI_KEY`.
 
-[ci-badge]: https://github.com/executablebooks/mdformat-plugin/workflows/CI/badge.svg?branch=master
+[ci-badge]: https://github.com/executablebooks/mdformat-hallmark/workflows/CI/badge.svg?branch=master
 [ci-link]: https://github.com/executablebooks/mdformat/actions?query=workflow%3ACI+branch%3Amaster+event%3Apush
-[cov-badge]: https://codecov.io/gh/executablebooks/mdformat-plugin/branch/master/graph/badge.svg
-[cov-link]: https://codecov.io/gh/executablebooks/mdformat-plugin
-[pypi-badge]: https://img.shields.io/pypi/v/mdformat-plugin.svg
-[pypi-link]: https://pypi.org/project/mdformat-plugin
+[cov-badge]: https://codecov.io/gh/executablebooks/mdformat-hallmark/branch/master/graph/badge.svg
+[cov-link]: https://codecov.io/gh/executablebooks/mdformat-hallmark
+[pypi-badge]: https://img.shields.io/pypi/v/mdformat-hallmark.svg
+[pypi-link]: https://pypi.org/project/mdformat-hallmark
diff --git a/mdformat_hallmark/__init__.py b/mdformat_hallmark/__init__.py
new file mode 100644
index 0000000..809d488
--- /dev/null
+++ b/mdformat_hallmark/__init__.py
@@ -0,0 +1,10 @@
+"""
+An mdformat plugin for compatibility with hallmark formatted Markdown
+and Common Changelog.
+"""
+
+__version__ = "0.0.1"
+
+from .hallmark_links_extension import HallmarkLinksExtension
+
+__all__ = ["HallmarkLinksExtension"]
diff --git a/mdformat_hallmark/hallmark_links_extension.py b/mdformat_hallmark/hallmark_links_extension.py
new file mode 100644
index 0000000..b7cdeaf
--- /dev/null
+++ b/mdformat_hallmark/hallmark_links_extension.py
@@ -0,0 +1,109 @@
+from dataclasses import dataclass
+import re
+
+from markdown_it import MarkdownIt
+from markdown_it.token import Token
+from mdformat.plugins import ParserExtensionInterface
+from mdformat.renderer import RenderContext, RenderTreeNode
+from packaging.version import InvalidVersion, Version
+
+_REFERENCES_RE = re.compile(
+    r'^\[([^\]]+)\]:\s*(\S+)(?:\s+"([^"]+)")?$',
+    re.MULTILINE,
+)  # regex for `[label]: href "title"`
+
+
+@dataclass
+class SemverReference:
+    semver: Version
+    label: str
+    href: str
+    title: str | None
+
+    def __str__(self):
+        line = f"[{self.label}]: {self.href}"
+        if self.title:
+            line += f' "{self.title}"'
+        return line
+
+
+def _extract_semver_references(src: str) -> tuple[list[SemverReference], str]:
+    refs: list[SemverReference] = []
+    remove_spans: list[tuple[int, int]] = []
+
+    for m in _REFERENCES_RE.finditer(src):
+        label, href, title = m.groups()
+        try:
+            semver = Version(label)
+        except InvalidVersion:
+            continue  # skip non-semver labels
+        refs.append(SemverReference(semver, label, href, title))
+        remove_spans.append(m.span())
+
+    # remove references from the source
+    out_src = src
+    for start, end in reversed(remove_spans):
+        out_src = out_src[:start] + out_src[end:]
+
+    # Normalize whitespace
+    out_src = re.sub(r"\n{3,}", "\n\n", out_src).rstrip()
+
+    # sort semver references
+    refs.sort(key=lambda ref: ref.semver, reverse=True)
+
+    return refs, out_src
+
+
+class HallmarkLinksExtension(ParserExtensionInterface):
+    """
+    mdformat plugin extension to format references used by versions and
+    renders sorted by semantic-version order.
+    """
+
+    @staticmethod
+    def update_mdit(mdit: MarkdownIt) -> None:
+        """Patch the default parser to render references in semver order."""
+
+        original_parse = mdit.parse
+
+        def new_parse(src: str, env=None):
+            if env is None:
+                env = {}
+            if not src.lstrip().startswith("# Changelog"):
+                return original_parse(src, env)
+
+            # extract semver references and remove from src
+            matches, out_src = _extract_semver_references(src)
+            refs = {
+                match.label: {"href": match.href, "title": match.title}
+                for match in matches
+            }
+
+            # call original parse on the cleaned text
+            tokens = original_parse(out_src, env)
+
+            # append a hallmark_refs token at the end
+            if refs:
+                token = Token("hallmark_refs", "", 0)
+                token.meta = {"refs": refs}
+                tokens.append(token)
+
+            return tokens
+
+        # patch parser
+        mdit.parse = new_parse
+
+    @staticmethod
+    def _render_hallmark_refs(node: RenderTreeNode, ctx: RenderContext) -> str:
+        """Render collected reference defs in hallmark ordered format."""
+        refs: dict[str, dict[str, str]] = node.meta["refs"]
+        out = []
+        for label, ref in refs.items():
+            line = f"[{label}]: {ref['href']}"
+            if ref.get("title"):
+                line += f' "{ref["title"]}"'
+            out.append(line)
+        return "\n\n".join(out)
+
+    RENDERERS = {"hallmark_refs": _render_hallmark_refs}
+    CHANGES_AST = True
diff --git a/mdformat_plugin/__init__.py b/mdformat_plugin/__init__.py
deleted file mode 100644
index 1c98271..0000000
--- a/mdformat_plugin/__init__.py
+++ /dev/null
@@ -1,5 +0,0 @@
-"""An mdformat plugin for..."""
-
-__version__ = "0.0.1"
-
-from .plugin import RENDERERS, update_mdit  # noqa: F401
diff --git a/mdformat_plugin/plugin.py b/mdformat_plugin/plugin.py
deleted file mode 100644
index 8fff61c..0000000
--- a/mdformat_plugin/plugin.py
+++ /dev/null
@@ -1,24 +0,0 @@
-from typing import Mapping
-
-from markdown_it import MarkdownIt
-from mdformat.renderer import RenderContext, RenderTreeNode
-from mdformat.renderer.typing import Render
-
-
-def update_mdit(mdit: MarkdownIt) -> None:
-    """Update the parser, e.g. by adding a plugin: `mdit.use(myplugin)`"""
-    pass
-
-
-def _render_table(node: RenderTreeNode, context: RenderContext) -> str:
-    """Render a `RenderTreeNode` of type "table".
-
-    Change "table" to the name of the syntax you want to render.
-    """
-    return ""
-
-
-# A mapping from syntax tree node type to a function that renders it.
-# This can be used to overwrite renderer functions of existing syntax
-# or add support for new syntax.
-RENDERERS: Mapping[str, Render] = {"table": _render_table}
diff --git a/pyproject.toml b/pyproject.toml
index d728245..a66eeb6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,9 +3,9 @@ requires = ["flit_core >=3.2.0,<4"]
 build-backend = "flit_core.buildapi"
 
 [project]
-name = "mdformat_plugin"
+name = "mdformat-hallmark"
 authors = [
-    { name = "Chris Sewell", email = "executablebooks@gmail.com" },
+    { name = "Callan Gray", email = "cal.j.gray@gmail.com" },
 ]
 readme = "README.md"
 classifiers = [
@@ -18,6 +18,7 @@ keywords = ["mdformat", "markdown", "markdown-it"]
 requires-python = ">=3.7"
 dependencies = [
     "mdformat >=0.7.0,<0.8.0",
+    "packaging >= 23.0",
 ]
 dynamic = ["version", "description"]
 
@@ -30,10 +31,10 @@ test = [
 dev = ["pre-commit"]
 
 [project.urls]
-Homepage = "https://github.com/executablebooks/mdformat-plugin"
+Homepage = "https://github.com/calgray/mdformat-hallmark"
 
 [project.entry-points."mdformat.parser_extension"]
-plugin = "mdformat_plugin"
+"hallmark" = "mdformat_hallmark:HallmarkLinksExtension"
 
 [tool.flit.sdist]
 include = []
@@ -46,7 +47,10 @@ force_sort_within_sections = true
 no_lines_before = ["LOCALFOLDER"]
 
 # Configure isort to work without access to site-packages
-known_first_party = ["mdformat_plugin", "tests"]
+known_first_party = ["mdformat_hallmark", "tests"]
 
 # Settings for Black compatibility
 profile = "black"
+
+[tool.pytest.ini_options]
+log_cli = true
diff --git a/tests/fixtures.md b/tests/fixtures.md
index 31d6be2..a1cd460 100644
--- a/tests/fixtures.md
+++ b/tests/fixtures.md
@@ -1,24 +1,161 @@
-a test
+not changelog test
 .
 This is the input Markdown test,
 then below add the expected output.
+
+- a [reference][]
+- b [0.0.1]
+* c [1.0.0]
+
+[unused reference]: https://example.com
+[0.0.1]: https://example.com
+[reference]: https://example.com
+[1.0.0]: https://example.com
 .
 This is the input Markdown test,
 then below add the expected output.
+
+- a [reference]
+- b [0.0.1]
+
+* c [1.0.0]
+
+[0.0.1]: https://example.com
+[1.0.0]: https://example.com
+[reference]: https://example.com
 .
 
-another test
+correct changelog test
 .
-Some *markdown*
+# Changelog
+
+## [10.1.0] - 2025-01-01
+
+## [2.10.0] - 2025-01-01
+
+## [2.0.0] - 2025-01-01
+
+## [1.0.10] - 2025-01-01
+
+## [1.0.0] - 2025-01-01
+
+## [0.0.10] - 2025-01-01
+
+## [0.0.2] - 2025-01-01
+
+## [0.0.1] - 2025-01-01
+
+[10.1.0]: https://example.com
+
+[2.10.0]: https://example.com
+
+[2.0.0]: https://example.com
 
-- a
-- b
-* c
+[1.0.10]: https://example.com
+
+[1.0.0]: https://example.com
+
+[0.0.10]: https://example.com
+
+[0.0.2]: https://example.com
+
+[0.0.1]: https://example.com
 .
-Some *markdown*
+# Changelog
+
+## [10.1.0] - 2025-01-01
+
+## [2.10.0] - 2025-01-01
+
+## [2.0.0] - 2025-01-01
+
+## [1.0.10] - 2025-01-01
+
+## [1.0.0] - 2025-01-01
+
+## [0.0.10] - 2025-01-01
+
+## [0.0.2] - 2025-01-01
+
+## [0.0.1] - 2025-01-01
+
+[10.1.0]: https://example.com
+
+[2.10.0]: https://example.com
+
+[2.0.0]: https://example.com
+
+[1.0.10]: https://example.com
+
+[1.0.0]: https://example.com
+
+[0.0.10]: https://example.com
+
+[0.0.2]: https://example.com
+
+[0.0.1]: https://example.com
+.
+
+unsorted changelog test
+.
+# Changelog
+
+## [10.1.0] - 2025-01-01
+
+## [2.0.0] - 2025-01-01
+
+## [2.10.0] - 2025-01-01
+
+## [1.0.10] - 2025-01-01
+
+## [1.0.0] - 2025-01-01
+
+## [0.0.10] - 2025-01-01
+
+## [0.0.2] - 2025-01-01
+
+## [0.0.1] - 2025-01-01
+
+[0.0.1]: https://example.com
+[0.0.2]: https://example.com
+[0.0.10]: https://example.com
+[1.0.0]: https://example.com
+[1.0.10]: https://example.com
+[2.0.0]: https://example.com
+[2.10.0]: https://example.com
+[10.1.0]: https://example.com
+.
+# Changelog
+
+## [10.1.0] - 2025-01-01
+
+## [2.0.0] - 2025-01-01
+
+## [2.10.0] - 2025-01-01
+
+## [1.0.10] - 2025-01-01
+
+## [1.0.0] - 2025-01-01
+
+## [0.0.10] - 2025-01-01
+
+## [0.0.2] - 2025-01-01
+
+## [0.0.1] - 2025-01-01
+
+[10.1.0]: https://example.com
+
+[2.10.0]: https://example.com
+
+[2.0.0]: https://example.com
+
+[1.0.10]: https://example.com
+
+[1.0.0]: https://example.com
+
+[0.0.10]: https://example.com
 
-- a
-- b
+[0.0.2]: https://example.com
 
-* c
+[0.0.1]: https://example.com
 .
diff --git a/tests/test_fixtures.py b/tests/test_fixtures.py
index 68fc3bf..c805a5a 100644
--- a/tests/test_fixtures.py
+++ b/tests/test_fixtures.py
@@ -12,6 +12,6 @@
     "line,title,text,expected", fixtures, ids=[f[1] for f in fixtures]
 )
 def test_fixtures(line, title, text, expected):
-    output = mdformat.text(text, extensions={"plugin"})
-    print(output)
+    output = mdformat.text(text, extensions={"hallmark"})
+    # output = mdformat.text(text, codeformatters={"python"})
     assert output.rstrip() == expected.rstrip(), output
diff --git a/tox.ini b/tox.ini
index c284ba3..4ad3108 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@ commands = pytest {posargs}
 
 [testenv:py{36,37,38,39}-cov]
 extras = test
-commands = pytest --cov={envsitepackagesdir}/mdformat_plugin {posargs}
+commands = pytest --cov={envsitepackagesdir}/mdformat_hallmark {posargs}
 
 [testenv:py{36,37,38,39}-pre-commit]
 extras = dev