diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b9b979d..c8c2cd0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -16,13 +16,11 @@ jobs:
           - macos-latest
 
         python:
-          - "3.7"
-          - "3.8"
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"
-          - "pypy3.9"
+          - "3.13"
+          - "3.14"
 
     steps:
       - uses: actions/checkout@v4
@@ -34,15 +32,12 @@ jobs:
 
       - name: Install
         run: |
-          pip install coverage
-          pip install -e .[test]
+          make install
 
       - name: Run tests
         run: |
-          python --version
-          python -m plumber.tests.__init__
+          make test
 
       - name: Run coverage
         run: |
-          coverage run -m plumber.tests.__init__
-          coverage report --fail-under=98
+          make coverage
diff --git a/.gitignore b/.gitignore
index 584028d..845d095 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@
 /htmlcov/
 /requirements-mxdev.txt
 /venv
+/build
diff --git a/CHANGES.rst b/CHANGES.rst
index a659f04..cd930be 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,7 +4,11 @@ Changes
 1.8 (unreleased)
 ----------------
 
-- Nothing changed yet.
+- Refactor package layout to use ``pyproject.toml`` and implicit namespace packages.
+  [rnix]
+
+- Drop Python 2 support.
+  [rnix]
 
 
 1.7 (2022-03-17)
diff --git a/LICENSE.rst b/LICENSE.rst
index 64b6915..2e9776a 100644
--- a/LICENSE.rst
+++ b/LICENSE.rst
@@ -2,7 +2,7 @@ License
 =======
 
 Copyright (c) 2011-2021, BlueDynamics Alliance, Austria, Germany, Switzerland
-Copyright (c) 2021-2022, Node Contributors
+Copyright (c) 2021-2025, Node Contributors
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/MANIFEST.in b/MANIFEST.in
deleted file mode 100644
index 40c2444..0000000
--- a/MANIFEST.in
+++ /dev/null
@@ -1,4 +0,0 @@
-include *.rst
-recursive-include src *
-recursive-exclude src *.pyc *.pyo
-prune scripts
diff --git a/Makefile b/Makefile
index addf311..5debf0f 100644
--- a/Makefile
+++ b/Makefile
@@ -32,18 +32,42 @@ CLEAN_FS?=
 # Default: include.mk
 INCLUDE_MAKEFILE?=include.mk
 
+# Optional additional directories to be added to PATH in format
+# `/path/to/dir/:/path/to/other/dir`. Gets inserted first, thus gets searched
+# first.
+# No default value.
+EXTRA_PATH?=
+
 ## core.mxenv
 
-# Python interpreter to use.
+# Primary Python interpreter to use. It is used to create the
+# virtual environment if `VENV_ENABLED` and `VENV_CREATE` are set to `true`.
+# If global `uv` is used, this value is passed as `--python VALUE` to the venv creation.
+# uv then downloads the Python interpreter if it is not available.
+# for more on this feature read the [uv python documentation](https://docs.astral.sh/uv/concepts/python-versions/)
 # Default: python3
-PYTHON_BIN?=python3
+PRIMARY_PYTHON?=python3
 
 # Minimum required Python version.
-# Default: 3.7
-PYTHON_MIN_VERSION?=3.7
+# Default: 3.9
+PYTHON_MIN_VERSION?=3.10
+
+# Install packages using the given package installer method.
+# Supported are `pip` and `uv`. If uv is used, its global availability is
+# checked. Otherwise, it is installed, either in the virtual environment or
+# using the `PRIMARY_PYTHON`, dependent on the `VENV_ENABLED` setting. If
+# `VENV_ENABLED` and uv is selected, uv is used to create the virtual
+# environment.
+# Default: pip
+PYTHON_PACKAGE_INSTALLER?=uv
+
+# Flag whether to use a global installed 'uv' or install
+# it in the virtual environment.
+# Default: false
+MXENV_UV_GLOBAL?=false
 
 # Flag whether to use virtual environment. If `false`, the
-# interpreter according to `PYTHON_BIN` found in `PATH` is used.
+# interpreter according to `PRIMARY_PYTHON` found in `PATH` is used.
 # Default: true
 VENV_ENABLED?=true
 
@@ -58,7 +82,7 @@ VENV_CREATE?=true
 # target folder for the virtual environment. If `VENV_ENABLED` is `true` and
 # `VENV_CREATE` is false it is expected to point to an existing virtual
 # environment. If `VENV_ENABLED` is `false` it is ignored.
-# Default: venv
+# Default: .venv
 VENV_FOLDER?=venv
 
 # mxdev to install in virtual environment.
@@ -81,12 +105,19 @@ RUFF_SRC?=src
 # Default: mx.ini
 PROJECT_CONFIG?=mx.ini
 
+## core.packages
+
+# Allow prerelease and development versions.
+# By default, the package installer only finds stable versions.
+# Default: false
+PACKAGES_ALLOW_PRERELEASES?=false
+
 ## qa.test
 
 # The command which gets executed. Defaults to the location the
 # :ref:`run-tests` template gets rendered to if configured.
 # Default: .mxmake/files/run-tests.sh
-TEST_COMMAND?=$(VENV_FOLDER)/bin/python -m plumber.tests.__init__
+TEST_COMMAND?=pytest tests
 
 # Additional Python requirements for running tests to be
 # installed (via pip).
@@ -103,9 +134,10 @@ TEST_DEPENDENCY_TARGETS?=
 # :ref:`run-coverage` template gets rendered to if configured.
 # Default: .mxmake/files/run-coverage.sh
 COVERAGE_COMMAND?=\
-	$(VENV_FOLDER)/bin/coverage run \
-		-m plumber.tests.__init__ \
-	&& $(VENV_FOLDER)/bin/coverage report --fail-under=98
+	coverage run \
+		--source=src/plumber \
+		-m pytest tests \
+	&& coverage report --fail-under=99
 
 ##############################################################################
 # END SETTINGS - DO NOT EDIT BELOW THIS LINE
@@ -119,6 +151,8 @@ CHECK_TARGETS?=
 TYPECHECK_TARGETS?=
 FORMAT_TARGETS?=
 
+export PATH:=$(if $(EXTRA_PATH),$(EXTRA_PATH):,)$(PATH)
+
 # Defensive settings for make: https://tech.davis-hansson.com/p/make/
 SHELL:=bash
 .ONESHELL:
@@ -135,7 +169,7 @@ MXMAKE_FOLDER?=.mxmake
 # Sentinel files
 SENTINEL_FOLDER?=$(MXMAKE_FOLDER)/sentinels
 SENTINEL?=$(SENTINEL_FOLDER)/about.txt
-$(SENTINEL):
+$(SENTINEL): $(firstword $(MAKEFILE_LIST))
 	@mkdir -p $(SENTINEL_FOLDER)
 	@echo "Sentinels for the Makefile process." > $(SENTINEL)
 
@@ -143,40 +177,62 @@ $(SENTINEL):
 # mxenv
 ##############################################################################
 
-# Check if given Python is installed
-ifeq (,$(shell which $(PYTHON_BIN)))
-$(error "PYTHON=$(PYTHON_BIN) not found in $(PATH)")
-endif
+OS?=
 
-# Check if given Python version is ok
-PYTHON_VERSION_OK=$(shell $(PYTHON_BIN) -c "import sys; print((int(sys.version_info[0]), int(sys.version_info[1])) >= tuple(map(int, '$(PYTHON_MIN_VERSION)'.split('.'))))")
-ifeq ($(PYTHON_VERSION_OK),0)
-$(error "Need Python >= $(PYTHON_MIN_VERSION)")
+# Determine the executable path
+ifeq ("$(VENV_ENABLED)", "true")
+export VIRTUAL_ENV=$(abspath $(VENV_FOLDER))
+ifeq ("$(OS)", "Windows_NT")
+VENV_EXECUTABLE_FOLDER=$(VIRTUAL_ENV)/Scripts
+else
+VENV_EXECUTABLE_FOLDER=$(VIRTUAL_ENV)/bin
 endif
-
-# Check if venv folder is configured if venv is enabled
-ifeq ($(shell [[ "$(VENV_ENABLED)" == "true" && "$(VENV_FOLDER)" == "" ]] && echo "true"),"true")
-$(error "VENV_FOLDER must be configured if VENV_ENABLED is true")
+export PATH:=$(VENV_EXECUTABLE_FOLDER):$(PATH)
+MXENV_PYTHON=python
+else
+MXENV_PYTHON=$(PRIMARY_PYTHON)
 endif
 
-# determine the executable path
-ifeq ("$(VENV_ENABLED)", "true")
-MXENV_PATH=$(VENV_FOLDER)/bin/
+# Determine the package installer
+ifeq ("$(PYTHON_PACKAGE_INSTALLER)","uv")
+PYTHON_PACKAGE_COMMAND=uv pip
 else
-MXENV_PATH=
+PYTHON_PACKAGE_COMMAND=$(MXENV_PYTHON) -m pip
 endif
 
 MXENV_TARGET:=$(SENTINEL_FOLDER)/mxenv.sentinel
 $(MXENV_TARGET): $(SENTINEL)
+ifneq ("$(PYTHON_PACKAGE_INSTALLER)$(MXENV_UV_GLOBAL)","uvfalse")
+	@$(PRIMARY_PYTHON) -c "import sys; vi = sys.version_info; sys.exit(1 if (int(vi[0]), int(vi[1])) >= tuple(map(int, '$(PYTHON_MIN_VERSION)'.split('.'))) else 0)" \
+		&& echo "Need Python >= $(PYTHON_MIN_VERSION)" && exit 1 || :
+else
+	@echo "Use Python $(PYTHON_MIN_VERSION) over uv"
+endif
+	@[[ "$(VENV_ENABLED)" == "true" && "$(VENV_FOLDER)" == "" ]] \
+		&& echo "VENV_FOLDER must be configured if VENV_ENABLED is true" && exit 1 || :
+	@[[ "$(VENV_ENABLED)$(PYTHON_PACKAGE_INSTALLER)" == "falseuv" ]] \
+		&& echo "Package installer uv does not work with a global Python interpreter." && exit 1 || :
 ifeq ("$(VENV_ENABLED)", "true")
 ifeq ("$(VENV_CREATE)", "true")
-	@echo "Setup Python Virtual Environment under '$(VENV_FOLDER)'"
-	@$(PYTHON_BIN) -m venv $(VENV_FOLDER)
+ifeq ("$(PYTHON_PACKAGE_INSTALLER)$(MXENV_UV_GLOBAL)","uvtrue")
+	@echo "Setup Python Virtual Environment using package 'uv' at '$(VENV_FOLDER)'"
+	@uv venv -p $(PRIMARY_PYTHON) --seed $(VENV_FOLDER)
+else
+	@echo "Setup Python Virtual Environment using module 'venv' at '$(VENV_FOLDER)'"
+	@$(PRIMARY_PYTHON) -m venv $(VENV_FOLDER)
+	@$(MXENV_PYTHON) -m ensurepip -U
+endif
+endif
+else
+	@echo "Using system Python interpreter"
 endif
+ifeq ("$(PYTHON_PACKAGE_INSTALLER)$(MXENV_UV_GLOBAL)","uvfalse")
+	@echo "Install uv"
+	@$(MXENV_PYTHON) -m pip install uv
 endif
-	@$(MXENV_PATH)pip install -U pip setuptools wheel
-	@$(MXENV_PATH)pip install -U $(MXDEV)
-	@$(MXENV_PATH)pip install -U $(MXMAKE)
+	@$(PYTHON_PACKAGE_COMMAND) install -U pip setuptools wheel
+	@echo "Install/Update MXStack Python packages"
+	@$(PYTHON_PACKAGE_COMMAND) install -U $(MXDEV) $(MXMAKE)
 	@touch $(MXENV_TARGET)
 
 .PHONY: mxenv
@@ -193,8 +249,8 @@ ifeq ("$(VENV_CREATE)", "true")
 	@rm -rf $(VENV_FOLDER)
 endif
 else
-	@$(MXENV_PATH)pip uninstall -y $(MXDEV)
-	@$(MXENV_PATH)pip uninstall -y $(MXMAKE)
+	@$(PYTHON_PACKAGE_COMMAND) uninstall -y $(MXDEV)
+	@$(PYTHON_PACKAGE_COMMAND) uninstall -y $(MXMAKE)
 endif
 
 INSTALL_TARGETS+=mxenv
@@ -208,18 +264,18 @@ CLEAN_TARGETS+=mxenv-clean
 RUFF_TARGET:=$(SENTINEL_FOLDER)/ruff.sentinel
 $(RUFF_TARGET): $(MXENV_TARGET)
 	@echo "Install Ruff"
-	@$(MXENV_PATH)pip install ruff
+	@$(PYTHON_PACKAGE_COMMAND) install ruff
 	@touch $(RUFF_TARGET)
 
 .PHONY: ruff-check
 ruff-check: $(RUFF_TARGET)
 	@echo "Run ruff check"
-	@$(MXENV_PATH)ruff check $(RUFF_SRC)
+	@ruff check $(RUFF_SRC)
 
 .PHONY: ruff-format
 ruff-format: $(RUFF_TARGET)
 	@echo "Run ruff format"
-	@$(MXENV_PATH)ruff format $(RUFF_SRC)
+	@ruff format $(RUFF_SRC)
 
 .PHONY: ruff-dirty
 ruff-dirty:
@@ -227,7 +283,8 @@ ruff-dirty:
 
 .PHONY: ruff-clean
 ruff-clean: ruff-dirty
-	@test -e $(MXENV_PATH)pip && $(MXENV_PATH)pip uninstall -y ruff || :
+	@test -e $(MXENV_PYTHON) && $(MXENV_PYTHON) -m pip uninstall -y ruff || :
+	@rm -rf .ruff_cache
 
 INSTALL_TARGETS+=$(RUFF_TARGET)
 CHECK_TARGETS+=ruff-check
@@ -247,13 +304,11 @@ MXMAKE_FILES?=$(MXMAKE_FOLDER)/files
 
 # set environment variables for mxmake
 define set_mxfiles_env
-	@export MXMAKE_MXENV_PATH=$(1)
-	@export MXMAKE_FILES=$(2)
+	@export MXMAKE_FILES=$(1)
 endef
 
 # unset environment variables for mxmake
 define unset_mxfiles_env
-	@unset MXMAKE_MXENV_PATH
 	@unset MXMAKE_FILES
 endef
 
@@ -270,9 +325,9 @@ FILES_TARGET:=requirements-mxdev.txt
 $(FILES_TARGET): $(PROJECT_CONFIG) $(MXENV_TARGET) $(SOURCES_TARGET) $(LOCAL_PACKAGE_FILES)
 	@echo "Create project files"
 	@mkdir -p $(MXMAKE_FILES)
-	$(call set_mxfiles_env,$(MXENV_PATH),$(MXMAKE_FILES))
-	@$(MXENV_PATH)mxdev -n -c $(PROJECT_CONFIG)
-	$(call unset_mxfiles_env,$(MXENV_PATH),$(MXMAKE_FILES))
+	$(call set_mxfiles_env,$(MXMAKE_FILES))
+	@mxdev -n -c $(PROJECT_CONFIG)
+	$(call unset_mxfiles_env)
 	@test -e $(MXMAKE_FILES)/pip.conf && cp $(MXMAKE_FILES)/pip.conf $(VENV_FOLDER)/pip.conf || :
 	@touch $(FILES_TARGET)
 
@@ -301,11 +356,21 @@ ADDITIONAL_SOURCES_TARGETS?=
 
 INSTALLED_PACKAGES=$(MXMAKE_FILES)/installed.txt
 
+ifeq ("$(PACKAGES_ALLOW_PRERELEASES)","true")
+ifeq ("$(PYTHON_PACKAGE_INSTALLER)","uv")
+PACKAGES_PRERELEASES=--prerelease=allow
+else
+PACKAGES_PRERELEASES=--pre
+endif
+else
+PACKAGES_PRERELEASES=
+endif
+
 PACKAGES_TARGET:=$(INSTALLED_PACKAGES)
 $(PACKAGES_TARGET): $(FILES_TARGET) $(ADDITIONAL_SOURCES_TARGETS)
 	@echo "Install python packages"
-	@$(MXENV_PATH)pip install -r $(FILES_TARGET)
-	@$(MXENV_PATH)pip freeze > $(INSTALLED_PACKAGES)
+	@$(PYTHON_PACKAGE_COMMAND) install $(PACKAGES_PRERELEASES) -r $(FILES_TARGET)
+	@$(PYTHON_PACKAGE_COMMAND) freeze > $(INSTALLED_PACKAGES)
 	@touch $(PACKAGES_TARGET)
 
 .PHONY: packages
@@ -318,8 +383,8 @@ packages-dirty:
 .PHONY: packages-clean
 packages-clean:
 	@test -e $(FILES_TARGET) \
-		&& test -e $(MXENV_PATH)pip \
-		&& $(MXENV_PATH)pip uninstall -y -r $(FILES_TARGET) \
+		&& test -e $(MXENV_PYTHON) \
+		&& $(MXENV_PYTHON) -m pip uninstall -y -r $(FILES_TARGET) \
 		|| :
 	@rm -f $(PACKAGES_TARGET)
 
@@ -334,14 +399,14 @@ CLEAN_TARGETS+=packages-clean
 TEST_TARGET:=$(SENTINEL_FOLDER)/test.sentinel
 $(TEST_TARGET): $(MXENV_TARGET)
 	@echo "Install $(TEST_REQUIREMENTS)"
-	@$(MXENV_PATH)pip install $(TEST_REQUIREMENTS)
+	@$(PYTHON_PACKAGE_COMMAND) install $(TEST_REQUIREMENTS)
 	@touch $(TEST_TARGET)
 
 .PHONY: test
 test: $(FILES_TARGET) $(SOURCES_TARGET) $(PACKAGES_TARGET) $(TEST_TARGET) $(TEST_DEPENDENCY_TARGETS)
-	@echo "Run tests"
-	@test -z "$(TEST_COMMAND)" && echo "No test command defined"
-	@test -z "$(TEST_COMMAND)" || bash -c "$(TEST_COMMAND)"
+	@test -z "$(TEST_COMMAND)" && echo "No test command defined" && exit 1 || :
+	@echo "Run tests using $(TEST_COMMAND)"
+	@/usr/bin/env bash -c "$(TEST_COMMAND)"
 
 .PHONY: test-dirty
 test-dirty:
@@ -349,7 +414,7 @@ test-dirty:
 
 .PHONY: test-clean
 test-clean: test-dirty
-	@test -e $(MXENV_PATH)pip && $(MXENV_PATH)pip uninstall -y $(TEST_REQUIREMENTS) || :
+	@test -e $(MXENV_PYTHON) && $(MXENV_PYTHON) -m pip uninstall -y $(TEST_REQUIREMENTS) || :
 	@rm -rf .pytest_cache
 
 INSTALL_TARGETS+=$(TEST_TARGET)
@@ -363,14 +428,14 @@ DIRTY_TARGETS+=test-dirty
 COVERAGE_TARGET:=$(SENTINEL_FOLDER)/coverage.sentinel
 $(COVERAGE_TARGET): $(TEST_TARGET)
 	@echo "Install Coverage"
-	@$(MXENV_PATH)pip install -U coverage
+	@$(PYTHON_PACKAGE_COMMAND) install -U coverage
 	@touch $(COVERAGE_TARGET)
 
 .PHONY: coverage
 coverage: $(FILES_TARGET) $(SOURCES_TARGET) $(PACKAGES_TARGET) $(COVERAGE_TARGET)
-	@echo "Run coverage"
-	@test -z "$(COVERAGE_COMMAND)" && echo "No coverage command defined"
-	@test -z "$(COVERAGE_COMMAND)" || bash -c "$(COVERAGE_COMMAND)"
+	@test -z "$(COVERAGE_COMMAND)" && echo "No coverage command defined" && exit 1 || :
+	@echo "Run coverage using $(COVERAGE_COMMAND)"
+	@/usr/bin/env bash -c "$(COVERAGE_COMMAND)"
 
 .PHONY: coverage-dirty
 coverage-dirty:
@@ -378,13 +443,17 @@ coverage-dirty:
 
 .PHONY: coverage-clean
 coverage-clean: coverage-dirty
-	@test -e $(MXENV_PATH)pip && $(MXENV_PATH)pip uninstall -y coverage || :
+	@test -e $(MXENV_PYTHON) && $(MXENV_PYTHON) -m pip uninstall -y coverage || :
 	@rm -rf .coverage htmlcov
 
 INSTALL_TARGETS+=$(COVERAGE_TARGET)
 DIRTY_TARGETS+=coverage-dirty
 CLEAN_TARGETS+=coverage-clean
 
+##############################################################################
+# Custom includes
+##############################################################################
+
 -include $(INCLUDE_MAKEFILE)
 
 ##############################################################################
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..af525ec
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,44 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "plumber"
+version = "1.8.dev0"
+description = "An alternative to mixin-based extension of classes."
+readme = "README.rst"
+license = {text = "Simplified BSD"}
+authors = [{name = "Node Contributors", email = "dev@conestack.org"}]
+keywords = ["class", "extension", "mixin", "alternative"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "License :: OSI Approved :: Python Software Foundation License",
+    "Operating System :: OS Independent",
+    "Topic :: Software Development",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
+]
+
+[project.optional-dependencies]
+test = [
+    "zope.interface",
+]
+
+[project.urls]
+Homepage = "http://github.com/conestack/plumber"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/plumber"]
+
+[tool.zest-releaser]
+create-wheel = true
+
+[tool.ruff]
+target-version = "py310"
+
+[tool.ruff.format]
+quote-style = "single"
diff --git a/ruff.toml b/ruff.toml
deleted file mode 100644
index 5391c72..0000000
--- a/ruff.toml
+++ /dev/null
@@ -1,4 +0,0 @@
-target-version = "py37"
-
-[format]
-quote-style = "single"
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 81049c3..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,2 +0,0 @@
-[zest.releaser]
-create-wheel = yes
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 7ee3df4..0000000
--- a/setup.py
+++ /dev/null
@@ -1,51 +0,0 @@
-from setuptools import find_packages
-from setuptools import setup
-import os
-
-
-def read_file(name):
-    with open(os.path.join(os.path.dirname(__file__), name)) as f:
-        return f.read()
-
-
-version = '1.8.dev0'
-shortdesc = 'An alternative to mixin-based extension of classes.'
-longdesc = '\n\n'.join([read_file(name) for name in [
-    'README.rst',
-    'CHANGES.rst',
-    'LICENSE.rst'
-]])
-
-
-setup(
-    name='plumber',
-    version=version,
-    description=shortdesc,
-    long_description=longdesc,
-    classifiers=[
-        'Development Status :: 5 - Production/Stable',
-        'License :: OSI Approved :: Python Software Foundation License',
-        'Operating System :: OS Independent',
-        'Topic :: Software Development',
-        'Programming Language :: Python',
-        'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3.7',
-        'Programming Language :: Python :: 3.8',
-        'Programming Language :: Python :: 3.9',
-        'Programming Language :: Python :: 3.10'
-    ],
-    keywords='class extension mixin alternative',
-    author='Node Contributors',
-    author_email='dev@conestack.org',
-    url='http://github.com/conestack/plumber',
-    license='Simplified BSD',
-    packages=find_packages('src'),
-    package_dir={'': 'src'},
-    include_package_data=True,
-    zip_safe=True,
-    install_requires=['setuptools'],
-    extras_require=dict(test=['zope.interface']),
-    test_suite='plumber.tests',
-    entry_points="""
-    """
-)
diff --git a/src/plumber/__init__.py b/src/plumber/__init__.py
index 03eddc3..8f40049 100644
--- a/src/plumber/__init__.py
+++ b/src/plumber/__init__.py
@@ -1,4 +1,3 @@
-from __future__ import absolute_import  # noqa
 from .behavior import Behavior  # noqa
 from .exceptions import PlumbingCollision  # noqa
 from .instructions import default  # noqa
diff --git a/src/plumber/behavior.py b/src/plumber/behavior.py
index d94f70f..d195eb1 100644
--- a/src/plumber/behavior.py
+++ b/src/plumber/behavior.py
@@ -1,11 +1,8 @@
-from __future__ import absolute_import
-from plumber.compat import ITER_FUNC
-from plumber.compat import add_metaclass
-from plumber.instructions import Instruction
-from plumber.instructions import plumb
+from .instructions import Instruction
+from .instructions import plumb
 
 try:
-    from plumber.instructions import _implements
+    from .instructions import _implements
 
     ZOPE_INTERFACE_AVAILABLE = True
 except ImportError:  # pragma: no cover
@@ -51,22 +48,18 @@ class behaviormetaclass(type):
 
         >>> from plumber.behavior import Behavior
         >>> from plumber.behavior import behaviormetaclass
-        >>> from plumber.compat import add_metaclass
 
-        >>> @add_metaclass(behaviormetaclass)
-        ... class A(object):
+        ... class A(object, metaclass=behaviormetaclass):
         ...     pass
 
         >>> getattr(A, '__plumbing_instructions__', 'No behavior')
         'No behavior'
 
-        >>> @add_metaclass(behaviormetaclass)
-        ... class A(Behavior):
+        ... class A(Behavior, metaclass=behaviormetaclass):
         ...     pass
 
         >>> getattr(A, '__plumbing_instructions__', None) and 'Behavior'
         'Behavior'
-
     """
 
     def __init__(cls, name, bases, dct):
@@ -87,7 +80,7 @@ def __init__(cls, name, bases, dct):
         if ZOPE_INTERFACE_AVAILABLE:
             instructions.append(_implements(cls))
 
-        for name, item in getattr(cls.__dict__, ITER_FUNC)():
+        for name, item in cls.__dict__.items():
             # adopt instructions and enlist them
             if isinstance(item, Instruction):
                 item.__name__ = name
@@ -113,6 +106,5 @@ def __init__(cls, name, bases, dct):
 
 # Base class for plumbing behaviors: identification and metaclass setting
 # No doctest allowed here, it would be recognized as an instruction.
-@add_metaclass(behaviormetaclass)
-class Behavior(_Behavior):
+class Behavior(_Behavior, metaclass=behaviormetaclass):
     pass
diff --git a/src/plumber/compat.py b/src/plumber/compat.py
deleted file mode 100644
index 3191b90..0000000
--- a/src/plumber/compat.py
+++ /dev/null
@@ -1,30 +0,0 @@
-# Python compatibility support code
-import sys
-
-
-IS_PY2 = sys.version_info[0] < 3
-IS_PYPY = '__pypy__' in sys.builtin_module_names
-ITER_FUNC = 'iteritems' if IS_PY2 else 'items'
-STR_TYPE = basestring if IS_PY2 else str  # noqa
-
-
-def add_metaclass(metaclass):
-    """Class decorator for creating a class with a metaclass."""
-
-    # This is taken from six
-    def wrapper(cls):
-        orig_vars = cls.__dict__.copy()
-        orig_vars.pop('__dict__', None)
-        orig_vars.pop('__weakref__', None)
-        slots = orig_vars.get('__slots__')
-        # since add_metaclass is only used for behaviormetaclass, slots related
-        # code gets never called. we keep this snippet from the original
-        # code anyway and mark coverage report to ignore it.
-        if slots is not None:
-            if isinstance(slots, str):  # pragma: no cover
-                slots = [slots]
-            for slots_var in slots:  # pragma: no cover
-                orig_vars.pop(slots_var)
-        return metaclass(cls.__name__, cls.__bases__, orig_vars)
-
-    return wrapper
diff --git a/src/plumber/instructions.py b/src/plumber/instructions.py
index d7050c5..e3e2300 100644
--- a/src/plumber/instructions.py
+++ b/src/plumber/instructions.py
@@ -1,6 +1,4 @@
-from __future__ import absolute_import
-from plumber.compat import STR_TYPE
-from plumber.exceptions import PlumbingCollision
+from .exceptions import PlumbingCollision
 
 try:
     from zope.interface import classImplements
@@ -30,7 +28,6 @@ def payload(item):
 
         >>> payload(Instruction(Instruction(Foo))) is Foo
         True
-
     """
     if not isinstance(item, Instruction):
         return item
@@ -99,7 +96,6 @@ def plumb_str(leftdoc, rightdoc):
 
         >>> plumb_str(None, None) is None
         True
-
     """
     if leftdoc is None:
         return rightdoc
@@ -540,10 +536,9 @@ def ok(self, p1, p2):
                 <plumb 'None' of None payload=1>
               with:
                 <plumb 'None' of None payload=2>
-
         """
-        if isinstance(p1, STR_TYPE):
-            return isinstance(p2, STR_TYPE) or p2 is None
+        if isinstance(p1, str):
+            return isinstance(p2, str) or p2 is None
         if isinstance(p1, property):
             return isinstance(p2, property)
         if callable(p1):
@@ -551,7 +546,7 @@ def ok(self, p1, p2):
         return False
 
     def plumb(self, plbfunc, p1, p2):
-        if isinstance(p1, STR_TYPE):
+        if isinstance(p1, str):
             return plumb_str(p1, p2)
         if isinstance(p1, property):
             # XXX: This should be split up into instructions during part
@@ -634,7 +629,6 @@ class _implements(Stage2Instruction):
                 <_implements '__interfaces__' of None payload=('foo',)>
               with:
                 <Instruction 'None' of None payload='bar'>
-
         """
 
         __name__ = '__interfaces__'
diff --git a/src/plumber/plumber.py b/src/plumber/plumber.py
index d84d85c..a489bc8 100644
--- a/src/plumber/plumber.py
+++ b/src/plumber/plumber.py
@@ -1,5 +1,4 @@
-from __future__ import absolute_import
-from plumber.behavior import Instructions
+from .behavior import Instructions
 
 
 class Stacks(object):
diff --git a/src/plumber/tests/__init__.py b/src/plumber/tests/__init__.py
deleted file mode 100644
index 75e035d..0000000
--- a/src/plumber/tests/__init__.py
+++ /dev/null
@@ -1,38 +0,0 @@
-from plumber import compat
-from pprint import pprint
-import doctest
-import sys
-import unittest
-
-
-optionflags = (
-    doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS | doctest.REPORT_ONLY_FIRST_FAILURE
-)
-
-
-if not compat.IS_PY2 and not compat.IS_PYPY:  # pragma: no cover
-    TESTFILES = ['../../../README.rst', '../behavior.py', '../instructions.py']
-else:  # pragma: no cover
-    TESTFILES = []
-
-
-def test_suite():
-    from plumber.tests import test_plumber
-
-    suite = unittest.TestSuite()
-    suite.addTest(unittest.findTestCases(test_plumber))
-    suite.addTests(
-        [
-            doctest.DocFileSuite(
-                testfile, globs=dict(pprint=pprint), optionflags=optionflags
-            )
-            for testfile in TESTFILES
-        ]
-    )
-    return suite
-
-
-if __name__ == '__main__':
-    runner = unittest.TextTestRunner(failfast=True)
-    result = runner.run(test_suite())
-    sys.exit(not result.wasSuccessful())
diff --git a/src/plumber/tests/globalmetaclass.py b/src/plumber/tests/globalmetaclass.py
deleted file mode 100644
index 7437c22..0000000
--- a/src/plumber/tests/globalmetaclass.py
+++ /dev/null
@@ -1,94 +0,0 @@
-"""A module to test setting a metaclass globally
-
-ATTENTION: we do not recommend this, but you can do it!
-
-Mostly here for understanding what's going on.
-"""
-from plumber import Behavior
-from plumber import plumber
-from plumber import plumbing
-from zope.interface import Interface
-from zope.interface import implementer
-
-
-__metaclass__ = plumber
-
-
-class IBehavior1(Interface):
-    """A zope.interface.Interface is not affected by the global
-    ``__metaclass__``.
-
-    .. code-block:: pycon
-
-        >>> IBehavior1.__class__
-        <class 'zope.interface.interface.InterfaceClass'>
-
-    """
-
-
-class Foo:
-    """A global meta-class declaration makes all classes at least new-style
-    classes, even when not subclassing subclasses.
-
-    .. code-block:: pycon
-
-        >>> Foo.__class__
-        <class 'plumber.plumber.plumber'>
-
-        >>> issubclass(Foo, object)
-        True
-
-    """
-
-
-@implementer(IBehavior1)
-class Behavior1(Behavior):
-    pass
-
-
-class ClassMaybeUsingAPlumbing(object):
-    """If subclassing object, the global metaclass declaration is ignored.
-
-    .. code-block:: pycon
-
-        >>> ClassMaybeUsingAPlumbing.__class__
-        <type 'type'>
-
-    """
-
-
-@plumbing(Behavior1)
-class ClassReallyUsingAPlumbing:
-    """A plumbing class.
-
-    .. code-block:: pycon
-
-        >>> ClassReallyUsingAPlumbing.__class__
-        <class 'plumber.plumber.plumber'>
-
-        >>> issubclass(ClassReallyUsingAPlumbing, object)
-        True
-
-        >>> IBehavior1.implementedBy(ClassReallyUsingAPlumbing)
-        True
-
-    """
-
-
-class BCClassReallyUsingAPlumbing:
-    """A plumbing class setting behaviors the B/C method.
-
-    .. code-block:: pycon
-
-        >>> BCClassReallyUsingAPlumbing.__class__
-        <class 'plumber.plumber.plumber'>
-
-        >>> issubclass(BCClassReallyUsingAPlumbing, object)
-        True
-
-        >>> IBehavior1.implementedBy(BCClassReallyUsingAPlumbing)
-        True
-
-    """
-
-    __plumbing__ = Behavior1
diff --git a/src/plumber/tests/test_plumber.py b/tests/test_plumber.py
similarity index 92%
rename from src/plumber/tests/test_plumber.py
rename to tests/test_plumber.py
index 657da4c..79f72b1 100644
--- a/src/plumber/tests/test_plumber.py
+++ b/tests/test_plumber.py
@@ -8,16 +8,13 @@
 from plumber import plumbifexists
 from plumber import plumbing
 from plumber.behavior import behaviormetaclass
-from plumber.compat import add_metaclass
 from plumber.instructions import Instruction
 from plumber.instructions import _implements
 from plumber.instructions import payload
 from plumber.instructions import plumb_str
 from zope.interface import Interface
 from zope.interface import implementer
-from zope.interface.interface import InterfaceClass
 import inspect
-import sys
 import unittest
 
 
@@ -229,16 +226,14 @@ def test_implements(self):
 
 class TestBehavior(unittest.TestCase):
     def test_behaviormetaclass(self):
-        @add_metaclass(behaviormetaclass)
-        class A(object):
+        class A(object, metaclass=behaviormetaclass):
             pass
 
         self.assertEqual(
             getattr(A, '__plumbing_instructions__', 'No behavior'), 'No behavior'
         )
 
-        @add_metaclass(behaviormetaclass)
-        class B(Behavior):
+        class B(Behavior, metaclass=behaviormetaclass):
             pass
 
         self.assertEqual(
@@ -258,35 +253,6 @@ class B(A):
         self.assertFalse('bar' in plumber.derived_members((B,)))
 
 
-class TestGlobalMetaclass(unittest.TestCase):
-    @unittest.skipIf(
-        sys.version_info[0] >= 3,
-        '__metaclass__ attribute on module leven only works in python 2',
-    )
-    def test_global_metaclass(self):
-        from plumber.tests import globalmetaclass as gm
-
-        # A zope.interface.Interface is not affected by the global
-        # ``__metaclass__``.
-        self.assertEqual(gm.IBehavior1.__class__, InterfaceClass)
-
-        # A global meta-class declaration makes all classes at least new-style
-        # classes, even when not subclassing subclasses
-        self.assertEqual(gm.Foo.__class__, plumber)
-        self.assertTrue(issubclass(gm.Foo, object))
-
-        # If subclassing object, the global metaclass declaration is ignored::
-        self.assertEqual(gm.ClassMaybeUsingAPlumbing.__class__, type)
-
-        self.assertEqual(gm.ClassReallyUsingAPlumbing.__class__, plumber)
-        self.assertTrue(issubclass(gm.ClassReallyUsingAPlumbing, object))
-        self.assertTrue(gm.IBehavior1.implementedBy(gm.ClassReallyUsingAPlumbing))
-
-        self.assertEqual(gm.BCClassReallyUsingAPlumbing.__class__, plumber)
-        self.assertTrue(issubclass(gm.BCClassReallyUsingAPlumbing, object))
-        self.assertTrue(gm.IBehavior1.implementedBy(gm.BCClassReallyUsingAPlumbing))
-
-
 class TestMetaclassHooks(unittest.TestCase):
     def test_metaclasshook(self):
         class IBehaviorInterface(Interface):
@@ -368,20 +334,6 @@ class Sub(Plumbing):
         stage2 = stacks.stage2
         self.assertEqual(sorted(list(stage2.keys())), ['__interfaces__'])
 
-    @unittest.skipIf(
-        sys.version_info[0] >= 3, '__metaclass__ property only works in python 2'
-    )
-    def test_bc_plumbing_py2(self):
-        class Behavior1(Behavior):
-            a = default(True)
-
-        class BCPlumbing(object):
-            __metaclass__ = plumber
-            __plumbing__ = Behavior1
-
-        plb = BCPlumbing()
-        self.assertTrue(plb.a)
-
 
 class TestPlumberStage1(unittest.TestCase):
     def test_finalize_instruction(self):