diff --git a/.github/workflows/unit-testing-and-coverage.yml b/.github/workflows/unit-testing-and-coverage.yml
index e867f071..b71a630d 100644
--- a/.github/workflows/unit-testing-and-coverage.yml
+++ b/.github/workflows/unit-testing-and-coverage.yml
@@ -7,14 +7,12 @@ on:
     branches: [ "master" ]
     paths:
       - "aiosmtpd/**"
-      - "setup.cfg"  # To monitor changes in dependencies
       - "pyproject.toml"  # To monitor changes in dependencies
   # This is for PRs
   pull_request:
     branches: [ "master" ]
     paths:
       - "aiosmtpd/**"
-      - "setup.cfg"  # To monitor changes in dependencies
       - "pyproject.toml"  # To monitor changes in dependencies
   # Manual/on-demand
   workflow_dispatch:
@@ -38,7 +36,7 @@ jobs:
         # language=bash
         run: |
           python -m pip install --upgrade pip setuptools wheel
-          python setup.py develop
+          python -m pip install .
           # Common deps
           pip install colorama
       - name: "flake8 Style Checking"
@@ -53,7 +51,9 @@ jobs:
             "print(config['flake8_plugins']['deps']);"
           )
           pip install "flake8>=5.0.4" $(python -c "${grab_f8_plugins[*]}")
-          python -m flake8 aiosmtpd setup.py housekeep.py release.py
+          echo "Running flake8 ... there will be no output if no errors:"
+          python -m flake8 aiosmtpd housekeep.py release.py
+          echo "flake8 done."
       - name: "Docs Checking"
         # language=bash
         run: |
@@ -69,6 +69,8 @@ jobs:
           pip install dnspython argon2-cffi
           # Install pytype
           pip install pytype
+          # List files & dirs so if pytype blows up we can see what else to exclude
+          ls -la
           pytype --keep-going --jobs auto .
       - name: "Other QA Checks"
         shell: bash
@@ -110,7 +112,7 @@ jobs:
         # Test deps
         pip install colorama "coverage>=7.0.1" coverage[toml] "coverage-conditional-plugin>=0.5.0" packaging pytest pytest-cov pytest-mock
         # Package deps
-        python setup.py develop
+        python -m pip install .
     - name: "Security checking"
       # language=bash
       run: |
diff --git a/README.rst b/README.rst
index 2714318a..9da5f02e 100644
--- a/README.rst
+++ b/README.rst
@@ -118,11 +118,12 @@ You can also request help by submitting a question on StackOverflow.
 Building
 ========
 
-You can install this package in a virtual environment like so::
+You can install this package -- after cloning -- in a virtual environment like so::
 
     $ python3 -m venv /path/to/venv
     $ source /path/to/venv/bin/activate
-    $ python setup.py install
+    $ python -m pip install -U pip setuptools
+    $ python -m pip install .
 
 This will give you a command line script called ``aiosmtpd`` which implements the
 SMTP server.  Use ``aiosmtpd --help`` for a quick reference.
diff --git a/aiosmtpd/__init__.py b/aiosmtpd/__init__.py
index 8cb1d719..e1be46c0 100644
--- a/aiosmtpd/__init__.py
+++ b/aiosmtpd/__init__.py
@@ -4,7 +4,7 @@
 import warnings
 
 
-__version__ = "1.4.4"
+__version__ = "1.5.0a1"
 
 
 def _get_or_new_eventloop() -> asyncio.AbstractEventLoop:
diff --git a/aiosmtpd/docs/NEWS.rst b/aiosmtpd/docs/NEWS.rst
index 405f1aed..65d8da9e 100644
--- a/aiosmtpd/docs/NEWS.rst
+++ b/aiosmtpd/docs/NEWS.rst
@@ -14,6 +14,7 @@ Fixed/Improved
 --------------
 * All Controllers now have more rationale design, as they are now composited from a Base + a Mixin
 * A whole bunch of annotations
+* Stop using ``setup.cfg`` and use ``pyproject.toml`` instead
 
 
 1.4.4 (2023-01-13)
diff --git a/pyproject.toml b/pyproject.toml
index 8731e605..e60189c2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,67 @@
+# region #### Project metadata ##########
+
+[project]
+name = "aiosmtpd"
+requires-python = ">=3.7"
+dynamic = [ "version" ]
+description = "aiosmtpd - asyncio based SMTP server"
+readme = "DESCRIPTION.rst"
+urls."Home Page" = "https://aiosmtpd.readthedocs.io/"
+urls."Bug Tracker" = "https://github.com/aio-libs/aiosmtpd/issues"
+urls."Documentation" = "https://aiosmtpd.readthedocs.io/"
+urls."Source Code" = "https://github.com/aio-libs/aiosmtpd"
+maintainers = [
+    { name = "The aiosmtpd Developers", email = "aiosmtpd@googlegroups.com"}
+]
+keywords = [ "email", "smtpd", "smtp", "async" ]
+license.file = "LICENSE"
+classifiers = [
+    "License :: OSI Approved",
+    "License :: OSI Approved :: Apache Software License",
+    "Intended Audience :: Developers",
+    "Operating System :: Microsoft :: Windows",
+    "Operating System :: POSIX :: BSD :: FreeBSD",
+    "Operating System :: POSIX :: Linux",
+    "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",
+    "Programming Language :: Python :: Implementation :: CPython",
+    "Programming Language :: Python :: Implementation :: PyPy",
+    "Topic :: Communications :: Email :: Mail Transport Agents",
+    "Framework :: AsyncIO",
+]
+dependencies = [
+    "atpublic",
+    "attrs",
+    "typing-extensions ; python_version < '3.8'",
+]
+
+[project.scripts]
+aiosmtpd = "aiosmtpd.main:main"
+
 [build-system]
 requires = ["setuptools", "wheel"]
 build-backend = "setuptools.build_meta"
 
+# endregion
+
+# region #### setuptools settings ##########
+
+[tool.setuptools]
+zip-safe = false
+
+[tool.setuptools.dynamic]
+version = { attr = "aiosmtpd.__version__" }
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["aiosmtpd*"]
+
+# endregion
+
 [tool.pytest.ini_options]
 addopts = """--strict-markers -rfEX"""
 markers = [
@@ -82,3 +142,85 @@ known_local_folder = [
     "aiosmtpd"
 ]
 combine_as_imports = true
+
+
+[tool.flake8]
+max-line-length = 88
+select = ["E", "F", "W", "C90", "C4", "MOD", "JS", "PIE", "PT", "SIM", "ECE", "C801", "DUO", "TAE", "ANN", "YTT", "N400"]
+ignore = [
+    # black conflicts with E123 & E133
+    "E123",
+    "E133",
+    # W503 conflicts with PEP8...
+    "W503",
+    # W293 is a bit too noisy. Many files have been edited using editors that do not remove spaces from blank lines.
+    "W293",
+    # Sometimes spaces around colons improve readability
+    "E203",
+    # Sometimes we prefer the func()-based creation, not literal, for readability
+    "C408",
+    # Sometimes we need to catch Exception broadly
+    "PIE786",
+    # We don't really care about pytest.fixture vs pytest.fixture()
+    "PT001",
+    # Good idea, but too many changes. Remove this in the future, and create separate PR
+    "PT004",
+    # Sometimes exception needs to be explicitly raised in special circumstances, needing additional lines of code
+    "PT012",
+    # I still can't grok the need to annotate "self" or "cls" ...
+    "ANN101",
+    "ANN102",
+    # I don't think forcing annotation for *args and **kwargs is a wise idea...
+    "ANN002",
+    "ANN003",
+    # We have too many "if..elif..else: raise" structures that does not convert well to "error-first" design
+    "SIM106",
+    # We have too many 'Any' type annotations.
+    "ANN401",
+    # Classes for some reason aren't always just replaceable by modules.
+    "PIE798",
+    # It is cleaner sometimes to assign and return, especially when using 'await' expressions.
+    "PIE781",
+    # Use f'strings instead of % formatters, the performance impact isn't too bad and f'strings are awesome!
+    "PIE803",
+    # It is more readable to instantiate and add items on-by-one instead of all at once.
+    "PIE799",
+    # Explicit is better than implicit, range(0, val) is more explicit than range(val).
+    "PIE808",
+]
+per-file-ignores = [
+    "aiosmtpd/tests/test_*:ANN001",
+    "aiosmtpd/tests/test_proxyprotocol.py:DUO102",
+    "aiosmtpd/docs/_exts/autoprogramm.py:C801",
+]
+# flake8-coding
+no-accept-encodings = true
+# flake8-copyright
+copyright-check = true
+# The number below was determined empirically by bisecting from 100 until no copyright-unnecessary files appear
+copyright-min-file-size = 44
+copyright-author = "The aiosmtpd Developers"
+# flake8-annotations-complexity
+max-annotations-complexity = 4
+# flake8-annotations-coverage
+min-coverage-percents = 12
+# flake8-annotations
+mypy-init-return = true
+suppress-none-returning = true
+suppress-dummy-args = true
+allow-untyped-defs = true
+
+
+[tool.pytype]
+exclude = [
+    "aiosmtpd/docs/_exts/*",
+    "_dump/*",
+    "aiosmtpd.egg-info/*",
+    "build/*",
+    "dist/*",
+    "Lib/*",
+    "Scripts/*",
+]
+disable = [
+    "not-supported-yet",
+]
diff --git a/release.py b/release.py
index e6313b3e..733fd65e 100755
--- a/release.py
+++ b/release.py
@@ -28,8 +28,12 @@
     f"dist/aiosmtpd-{ver_str}-py3-none-any.whl",
 ]
 
+RELEASE_TOOLKIT = ["setuptools", "wheel", "twine", "build"]
+
 printfl("Updating release toolkit first...", end="")
-run_hidden([sys.executable] + shlex.split("-m pip install -U setuptools wheel twine"))
+run_hidden(
+    [sys.executable] + shlex.split("-m pip install -U") + RELEASE_TOOLKIT
+)
 print()
 
 printfl("Checking extra toolkit...", end="")
@@ -91,10 +95,12 @@
 
 try:
     # Let's use *this* python to build, please
-    print("### setup.py sdist")
-    subprocess.run([sys.executable, "setup.py", "sdist"], check=True)
-    print("### setup.py sdist")
-    subprocess.run([sys.executable, "setup.py", "bdist_wheel"], check=True)
+    # print("### setup.py sdist")
+    # subprocess.run([sys.executable, "setup.py", "sdist"], check=True)
+    # print("### setup.py sdist")
+    # subprocess.run([sys.executable, "setup.py", "bdist_wheel"], check=True)
+    print("### build (sdist and wheel")
+    subprocess.run([sys.executable, "-m", "build"])
     for f in DISTFILES:
         assert Path(f).exists(), f"{f} is missing!"
 
@@ -116,7 +122,7 @@
 if has_verify:
     print("Waiting for package to be received by PyPI...", end="")
     for i in range(10, 0, -1):
-        printfl(i, end="..")
+        printfl(i, end="..", flush=True)
         time.sleep(1.0)
     print()
     twine_verif = ["twine", "verify_upload"] + DISTFILES
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index a00d13cf..00000000
--- a/setup.cfg
+++ /dev/null
@@ -1,135 +0,0 @@
-[metadata]
-name = aiosmtpd
-version = attr: aiosmtpd.__version__
-description = aiosmtpd - asyncio based SMTP server
-long_description = file: DESCRIPTION.rst
-long_description_content_type = text/x-rst
-url = https://aiosmtpd.readthedocs.io/
-project_urls =
-    Bug Tracker = https://github.com/aio-libs/aiosmtpd/issues
-    Documentation = https://aiosmtpd.readthedocs.io/
-    Source Code = https://github.com/aio-libs/aiosmtpd
-maintainer = The aiosmtpd Developers
-maintainer_email = aiosmtpd@googlegroups.com
-keywords = email, smtpd, smtp
-license = Apache-2.0
-classifiers =
-    License :: OSI Approved
-    License :: OSI Approved :: Apache Software License
-    Intended Audience :: Developers
-    Operating System :: Microsoft :: Windows
-    Operating System :: POSIX :: BSD :: FreeBSD
-    Operating System :: POSIX :: Linux
-    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
-    Programming Language :: Python :: Implementation :: CPython
-    Programming Language :: Python :: Implementation :: PyPy
-    Topic :: Communications :: Email :: Mail Transport Agents
-    Framework :: AsyncIO
-
-[options]
-zip_safe = false
-python_requires = ~=3.7
-packages = find:
-include_package_data = true
-setup_requires =
-    setuptools
-install_requires =
-    atpublic
-    attrs
-    typing-extensions ; python_version < '3.8'
-tests_require =
-    tox
-    setuptools
-
-[options.packages.find]
-exclude =
-    examples
-
-[options.entry_points]
-console_scripts =
-    aiosmtpd = aiosmtpd.main:main
-
-[easy_install]
-zip_ok = false
-
-[pytype]
-exclude =
-    aiosmtpd/docs/_exts/*
-    _dump/*
-disable =
-    not-supported-yet
-
-[build_sphinx]
-source-dir = aiosmtpd/docs
-
-[flake8]
-jobs = 1
-max-line-length = 88
-# "E,F,W,C90" are flake8 defaults
-# For others, take a gander at tox.ini to see which prefix provided by who
-select = E,F,W,C90,C4,MOD,JS,PIE,PT,SIM,ECE,C801,DUO,TAE,ANN,YTT,N400
-ignore =
-    # black conflicts with E123 & E133
-    E123
-    E133
-    # W503 conflicts with PEP8...
-    W503
-    # W293 is a bit too noisy. Many files have been edited using editors that do not remove spaces from blank lines.
-    W293
-    # Sometimes spaces around colons improve readability
-    E203
-    # Sometimes we prefer the func()-based creation, not literal, for readability
-    C408
-    # Sometimes we need to catch Exception broadly
-    PIE786
-    # We don't really care about pytest.fixture vs pytest.fixture()
-    PT001
-    # Good idea, but too many changes. Remove this in the future, and create separate PR
-    PT004
-    # Sometimes exception needs to be explicitly raised in special circumstances, needing additional lines of code
-    PT012
-    # I still can't grok the need to annotate "self" or "cls" ...
-    ANN101
-    ANN102
-    # I don't think forcing annotation for *args and **kwargs is a wise idea...
-    ANN002
-    ANN003
-    # We have too many "if..elif..else: raise" structures that does not convert well to "error-first" design
-    SIM106
-    # We have too many 'Any' type annotations.
-    ANN401
-    # Classes for some reason aren't always just replaceable by modules.
-    PIE798
-    # It is cleaner sometimes to assign and return, especially when using 'await' expressions.
-    PIE781
-    # Use f'strings instead of % formatters, the performance impact isn't too bad and f'strings are awesome!
-    PIE803
-    # It is more readable to instantiate and add items on-by-one instead of all at once.
-    PIE799
-    # Explicit is better than implicit, range(0, val) is more explicit than range(val).
-    PIE808
-per-file-ignores =
-    aiosmtpd/tests/test_*:ANN001
-    aiosmtpd/tests/test_proxyprotocol.py:DUO102
-    aiosmtpd/docs/_exts/autoprogramm.py:C801
-# flake8-coding
-no-accept-encodings = True
-# flake8-copyright
-copyright-check = True
-# The number below was determined empirically by bisecting from 100 until no copyright-unnecessary files appear
-copyright-min-file-size = 44
-copyright-author = The aiosmtpd Developers
-# flake8-annotations-complexity
-max-annotations-complexity = 4
-# flake8-annotations-coverage
-min-coverage-percents = 12
-# flake8-annotations
-mypy-init-return = True
-suppress-none-returning = True
-suppress-dummy-args = True
-allow-untyped-defs = True
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 60684932..00000000
--- a/setup.py
+++ /dev/null
@@ -1,3 +0,0 @@
-from setuptools import setup
-
-setup()
diff --git a/tox.ini b/tox.ini
index 211e78da..8a7939ee 100644
--- a/tox.ini
+++ b/tox.ini
@@ -54,11 +54,13 @@ passenv =
 [flake8_plugins]
 # This is a pseudo-section that feeds into [testenv:qa] and GA
 # Snippets of letters above these plugins are tests that need to be "select"-ed in flake8 config (in
-# setup.cfg) to activate the respective plugins. If no snippet is given, that means the plugin is
+# pyproject.toml) to activate the respective plugins. If no snippet is given, that means the plugin is
 # always active.
 # IMPORTANT: It's a good idea to restrict the version numbers of the plugins. Without version limits, GHCI's pip
 # sometimes simply gives up trying to figure the right deps, causing the test to fail.
+# IMPORTANT 2: Do not add spaces around the version limiter!
 deps =
+    flake8-pyproject>=1.2.2
     flake8-bugbear>=22.12.6
     flake8-builtins>=2.0.1
     flake8-coding>=1.3.2