diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 69a6313a..b17e21d7 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -23,10 +23,9 @@ jobs:
           - {name: Mac, python: '3.9', os: macos-latest, tox: py39}
           - {name: '3.8', python: '3.8', os: ubuntu-latest, tox: py38}
           - {name: '3.7', python: '3.7', os: ubuntu-latest, tox: py37}
-          - {name: '3.6', python: '3.6', os: ubuntu-latest, tox: py36}
           - {name: '2.7', python: '2.7', os: ubuntu-latest, tox: py27}
-          - {name: 'PyPy2', python: 'pypy2', os: ubuntu-latest, tox: pypy}
-          - {name: 'PyPy3', python: 'pypy3', os: ubuntu-latest, tox: pypy3}
+          - {name: 'PyPy2', python: 'pypy-2.7', os: ubuntu-latest, tox: pypy}
+          - {name: 'PyPy3', python: 'pypy-3.8', os: ubuntu-latest, tox: pypy3}
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
@@ -44,6 +43,6 @@ jobs:
         uses: actions/cache@v2
         with:
           path: ${{ steps.pip-cache.outputs.dir }}
-          key: pip|${{ runner.os }}|${{ matrix.python }}|${{ hashFiles('setup.py') }}|${{ hashFiles('requirements/*.txt') }}
+          key: pip|${{ runner.os }}|${{ matrix.python }}|${{ hashFiles('pyproject.toml') }}|${{ hashFiles('requirements/*.txt') }}
       - run: pip install tox
       - run: tox -e ${{ matrix.tox }}
diff --git a/MANIFEST.in b/MANIFEST.in
deleted file mode 100644
index 4a1617e6..00000000
--- a/MANIFEST.in
+++ /dev/null
@@ -1,8 +0,0 @@
-include CHANGELOG.md
-include LICENSE
-include README.md
-include TODO.rst
-include pytest.ini
-include tox.ini
-recursive-include docs 
-recursive-include tests
diff --git a/README.md b/README.md
index 665e2251..a4b8c0dd 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ in the same spirit as — and yet conspicuously missing from —
 **[Full and extensive docs are available on Read The Docs.][rtd]** See
 what's new [by checking the CHANGELOG][changelog].
 
-Boltons is tested against Python 2.6, 2.7, 3.4, 3.5, 3.6, 3.7, 3.8 and 3.9, as well as CPython
+Boltons is tested against Python 2.7, 3.7, 3.8 and 3.9, as well as CPython
 _nightly_ and PyPy/PyPy3.
 
 [stdlib]: https://docs.python.org/2.7/library/index.html
diff --git a/RELEASE.md b/RELEASE.md
new file mode 100644
index 00000000..ab0beef1
--- /dev/null
+++ b/RELEASE.md
@@ -0,0 +1,24 @@
+# Release
+
+-----
+
+Requirements:
+
+- `pip install -U build tox twine`
+
+A brief checklist for release:
+
+- `tox`
+- `git commit` (if applicable)
+- bump `boltons/__init__.py` version off of -dev
+- `git commit -a -m "bump version for x.y.z release"`
+- `python -m build`
+- `twine upload dist/*`
+- bump `docs/conf.py` version
+- `git commit`
+- `git tag -a x.y.z -m "brief summary"`
+- write `CHANGELOG.md`
+- `git commit`
+- bump `boltons/__init__.py` version onto n+1 dev
+- `git commit`
+- `git push`
diff --git a/boltons/__init__.py b/boltons/__init__.py
index e69de29b..72f65648 100644
--- a/boltons/__init__.py
+++ b/boltons/__init__.py
@@ -0,0 +1 @@
+__version__ = '22.0.0dev'
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..de4ac470
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,53 @@
+[build-system]
+requires = [
+    "hatchling>=0.17.0",
+]
+build-backend = "hatchling.build"
+
+[project]
+name = "boltons"
+description = "When they're not builtins, they're boltons."
+readme = "README.md"
+license = "BSD-3-Clause"
+authors = [
+    { name = "Mahmoud Hashemi", email = "mahmoud@hatnote.com" },
+]
+# https://pypi.org/classifiers/
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: BSD License",
+    "Operating System :: OS Independent",
+    "Topic :: Software Development :: Libraries",
+    "Topic :: Utilities",
+    # List of python versions and their support status:
+    # https://en.wikipedia.org/wiki/History_of_Python#Table_of_versions
+    "Programming Language :: Python :: 2",
+    "Programming Language :: Python :: 2.7",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: Implementation :: CPython",
+    "Programming Language :: Python :: Implementation :: PyPy",
+]
+dynamic = [
+    "version",
+]
+
+[project.urls]
+Homepage = "https://github.com/mahmoud/boltons"
+
+[tool.hatch.version]
+path = "boltons/__init__.py"
+
+[tool.hatch.build.targets.sdist]
+include = [
+    "/boltons",
+    "/docs",
+    "/tests",
+    "/CHANGELOG.md",
+    "/TODO.rst",
+    "/pytest.ini",
+    "/tox.ini",
+]
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 44d9e374..00000000
--- a/setup.cfg
+++ /dev/null
@@ -1,5 +0,0 @@
-[wheel]
-universal = 1
-
-[metadata]
-license_file = LICENSE
diff --git a/setup.py b/setup.py
deleted file mode 100644
index b2f1cca7..00000000
--- a/setup.py
+++ /dev/null
@@ -1,75 +0,0 @@
-"""Functionality that should be in the standard library. Like
-builtins, but Boltons.
-
-Otherwise known as, "everyone's util.py," but cleaned up and
-tested.
-
-Contains over 250 BSD-licensed utility types and functions that can be
-used as a package or independently. `Extensively documented on Read
-the Docs <http://boltons.readthedocs.org>`_.
-"""
-
-from setuptools import setup
-
-
-__author__ = 'Mahmoud Hashemi'
-__version__ = '21.0.1dev'
-__contact__ = 'mahmoud@hatnote.com'
-__url__ = 'https://github.com/mahmoud/boltons'
-__license__ = 'BSD'
-
-
-setup(name='boltons',
-      version=__version__,
-      description="When they're not builtins, they're boltons.",
-      long_description=__doc__,
-      author=__author__,
-      author_email=__contact__,
-      url=__url__,
-      packages=['boltons'],
-      include_package_data=True,
-      zip_safe=False,
-      license=__license__,
-      platforms='any',
-      classifiers=[
-          # See: https://pypi.python.org/pypi?:action=list_classifiers
-          'Topic :: Utilities',
-          'Intended Audience :: Developers',
-          'License :: OSI Approved :: BSD License',
-          'Topic :: Software Development :: Libraries',
-          'Development Status :: 5 - Production/Stable',
-          'Operating System :: OS Independent',
-          # List of python versions and their support status:
-          # https://en.wikipedia.org/wiki/CPython#Version_history
-          'Programming Language :: Python :: 2',
-          'Programming Language :: Python :: 2.6',
-          'Programming Language :: Python :: 2.7',
-          'Programming Language :: Python :: 3',
-          'Programming Language :: Python :: 3.4',
-          'Programming Language :: Python :: 3.5',
-          'Programming Language :: Python :: 3.6',
-          'Programming Language :: Python :: 3.7',
-          'Programming Language :: Python :: 3.8',
-          'Programming Language :: Python :: 3.9',
-          'Programming Language :: Python :: Implementation :: CPython',
-          'Programming Language :: Python :: Implementation :: PyPy', ]
-      )
-
-"""
-A brief checklist for release:
-
-* tox
-* git commit (if applicable)
-* Bump setup.py version off of -dev
-* git commit -a -m "bump version for x.y.z release"
-* python setup.py sdist bdist_wheel upload
-* bump docs/conf.py version
-* git commit
-* git tag -a x.y.z -m "brief summary"
-* write CHANGELOG
-* git commit
-* bump setup.py version onto n+1 dev
-* git commit
-* git push
-
-"""
diff --git a/tox.ini b/tox.ini
index 13929272..6c1f3ea9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,6 @@
 [tox]
-envlist = py27,py34,py37,py39,pypy
+isolated_build = true
+envlist = py27,py37,py39,pypy
 [testenv]
 changedir = .tox
 deps = -rrequirements-test.txt