diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 000000000..a0caa141e
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,258 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - dev
+      - master
+    tags:
+      - v*
+  pull_request:
+    branches:
+      - "*"
+  schedule:
+    # Daily at 05:14
+    - cron: '14 5 * * *'
+
+jobs:
+  test:
+    # Should match JOB_NAME below
+    name: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    runs-on: ${{ matrix.os.runs-on }}
+    container: ${{ matrix.os.container[matrix.python.docker] }}
+    strategy:
+      fail-fast: false
+      matrix:
+        task:
+          - name: Test
+            tox: test
+            coverage: true
+        os:
+          - name: Linux
+            runs-on: ubuntu-latest
+            python_platform: linux
+            matrix: linux
+            container:
+              2.7: docker://python:2.7-buster
+              3.6: docker://python:3.6-buster
+              3.7: docker://python:3.7-buster
+              3.8: docker://python:3.8-buster
+              3.9: docker://python:3.9-buster
+              pypy2: docker://pypy:2-jessie
+              pypy3: docker://pypy:3-stretch
+#          - name: Windows
+#            runs-on: windows-latest
+#            python_platform: win32
+#            matrix: windows
+#          - name: macOS
+#            runs-on: macos-latest
+#            python_platform: darwin
+#            matrix: macos
+        python:
+          - name: CPython 2.7
+            tox: py27
+            action: 2.7
+            docker: 2.7
+            implementation: cpython
+          - name: PyPy 2.7
+            tox: pypy27
+            action: pypy-2.7
+            docker: pypy2.7
+            implementation: pypy
+          - name: CPython 3.6
+            tox: py36
+            action: 3.6
+            docker: 3.6
+            implementation: cpython
+          - name: CPython 3.7
+            tox: py37
+            action: 3.7
+            docker: 3.7
+            implementation: cpython
+          - name: CPython 3.8
+            tox: py38
+            action: 3.8
+            docker: 3.8
+            implementation: cpython
+          - name: CPython 3.9
+            tox: py39
+            action: 3.9
+            docker: 3.9
+            implementation: cpython
+          - name: PyPy 3.6
+            tox: pypy36
+            action: pypy-3.6
+            docker: pypy3.6
+            implementation: pypy
+          - name: PyPy 3.7
+            tox: pypy37
+            action: pypy-3.7
+            docker: pypy3.7
+            implementation: pypy
+        arch:
+          - name: x86
+            action: x86
+            matrix: x86
+          - name: x64
+            action: x64
+            matrix: x64
+        exclude:
+          - os:
+              matrix: linux
+            arch:
+              matrix: x86
+          - os:
+              matrix: macos
+            arch:
+              matrix: x86
+    env:
+      # Should match name above
+      JOB_NAME: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up ${{ matrix.python.name }} (if CPython)
+        if: ${{ job.container == '' && matrix.python.implementation == 'cpython'}}
+        uses: actions/setup-python@v2
+        with:
+          python-version: '${{ matrix.python.action }}.0-alpha - ${{ matrix.python.action }}.X'
+          architecture: '${{ matrix.arch.action }}'
+      - name: Set up ${{ matrix.python.name }} (if PyPy)
+        if: ${{ job.container == '' && matrix.python.implementation == 'pypy'}}
+        uses: actions/setup-python@v2
+        with:
+          python-version: '${{ matrix.python.action }}'
+          architecture: '${{ matrix.arch.action }}'
+      - name: Install
+        run: |
+          pip install --upgrade pip setuptools wheel
+          pip install --upgrade tox
+      - uses: twisted/python-info-action@v1.0.1
+      - name: Test
+        run: |
+          tox -vv -e ${{ matrix.python.tox }}
+      - name: Coverage Processing
+        if: matrix.task.coverage
+        run: |
+          mkdir coverage_reports
+          cp .coverage "coverage_reports/.coverage.${{ env.JOB_NAME }}"
+          cp coverage.xml "coverage_reports/coverage.${{ env.JOB_NAME }}.xml"
+      - name: Upload Coverage
+        if: matrix.task.coverage
+        uses: actions/upload-artifact@v2
+        with:
+          name: coverage
+          path: coverage_reports/*
+  check:
+    # Should match JOB_NAME below
+    name: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    runs-on: ${{ matrix.os.runs-on }}
+    container: ${{ matrix.os.container[matrix.python.docker] }}
+    strategy:
+      fail-fast: false
+      matrix:
+        task:
+          - name: flake8
+            tox: flake8
+            continue_on_error: true
+          - name: Docs
+            tox: docs
+        os:
+          - name: Linux
+            runs-on: ubuntu-latest
+            python_platform: linux
+            matrix: linux
+            container:
+              3.8: docker://python:3.8-buster
+        python:
+          - name: CPython 3.8
+            tox: py38
+            action: 3.8
+            docker: 3.8
+            implementation: cpython
+        arch:
+          - name: x64
+            action: x64
+            matrix: x64
+    env:
+      # Should match name above
+      JOB_NAME: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Install
+        run: |
+          pip install --upgrade pip setuptools wheel
+          pip install --upgrade tox
+      - uses: twisted/python-info-action@v1.0.1
+      - name: Test
+        continue-on-error: ${{ matrix.task.continue_on_error == true }}
+        run: |
+          tox -vv -e ${{ matrix.task.tox }}
+  coverage:
+    # Should match JOB_NAME below
+    name: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    runs-on: ${{ matrix.os.runs-on }}
+    needs:
+      - test
+    container: ${{ matrix.os.container[matrix.python.docker] }}
+    strategy:
+      fail-fast: false
+      matrix:
+        task:
+          - name: Coverage
+            tox: combined-coverage
+            download_coverage: true
+        os:
+          - name: Linux
+            runs-on: ubuntu-latest
+            python_platform: linux
+            matrix: linux
+            container:
+              3.8: docker://python:3.8-buster
+        python:
+          - name: CPython 3.8
+            tox: py38
+            action: 3.8
+            docker: 3.8
+            implementation: cpython
+        arch:
+          - name: x64
+            action: x64
+            matrix: x64
+    env:
+      # Should match name above
+      JOB_NAME: ${{ matrix.task.name }} - ${{ matrix.os.name }} ${{ matrix.python.name }} ${{ matrix.arch.name }}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Install
+        run: |
+          pip install --upgrade pip setuptools wheel
+          pip install --upgrade tox
+      - uses: twisted/python-info-action@v1.0.1
+      - name: Download Coverage
+        if: matrix.task.download_coverage
+        uses: actions/download-artifact@v2
+        with:
+          name: coverage
+          path: coverage_reports
+      - name: Test
+        continue-on-error: ${{ matrix.task.continue_on_error == true }}
+        run: |
+          tox -vv -e ${{ matrix.task.tox }}
+  all:
+    name: All
+    runs-on: ubuntu-latest
+    needs:
+      - check
+      - coverage
+      - test
+    steps:
+      - name: This
+        shell: python
+        run: |
+          import this
diff --git a/doc/conf.py b/doc/conf.py
index 294b41b79..4f0dc4122 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -47,7 +47,7 @@
 # ones.
 
 #extensions = ['sphinx.ext.autodoc', 'm2r', 'recommonmark']
-extensions = ['sphinx.ext.autodoc', 'm2r']
+extensions = ['sphinx.ext.autodoc', 'm2r2']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
diff --git a/requirements-coverage.txt b/requirements-coverage.txt
new file mode 100644
index 000000000..9808587c9
--- /dev/null
+++ b/requirements-coverage.txt
@@ -0,0 +1 @@
+coverage >= 4.2
diff --git a/requirements-docs.txt b/requirements-docs.txt
index f1165c9c6..b0a4d2416 100644
--- a/requirements-docs.txt
+++ b/requirements-docs.txt
@@ -13,5 +13,5 @@ tornado>=4.5.3      # Required to parse some files
 Twisted>=17.1.0    # Required to parse some files
 prompt_toolkit>=2.0.4
 click>=7.0
-m2r>=0.2.0
+m2r2>=0.2.0
 
diff --git a/requirements-tests.txt b/requirements-tests.txt
index eba656a38..5eca1922c 100644
--- a/requirements-tests.txt
+++ b/requirements-tests.txt
@@ -1,6 +1,6 @@
 bcrypt>=3.1.6
 capturer >= 2.2
-coverage >= 4.2
+-r requirements-coverage.txt
 cryptography>= 2.3
 mock >= 1.0.1
 pyserial-asyncio>=0.4.0;python_version>="3.4"
@@ -14,6 +14,6 @@ sqlalchemy>=1.1.15
 #wsgiref>=0.1.2
 verboselogs >= 1.5
 tornado==4.5.3
-Twisted>=20.3.0
+Twisted[serial]>=20.3.0
 zope.interface>=4.4.0
 asynctest>=0.10.0
diff --git a/scripts/travis.sh b/scripts/travis.sh
deleted file mode 100755
index 8f4338270..000000000
--- a/scripts/travis.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/bin/bash -e
-set -x
-if [ "$TRAVIS_OS_NAME" = osx ]; then
-  VIRTUAL_ENV="$HOME/.virtualenvs/python2.7"
-  if [ ! -x "$VIRTUAL_ENV/bin/python" ]; then
-    virtualenv "$VIRTUAL_ENV"
-  fi
-  source "$VIRTUAL_ENV/bin/activate"
-fi
-
-eval "$@"
diff --git a/setup.py b/setup.py
index 50da034be..ce65b7d2c 100644
--- a/setup.py
+++ b/setup.py
@@ -89,7 +89,7 @@
                       'sphinx_rtd_theme',
                       'humanfriendly'],
         'twisted': [
-            'twisted >= 20.3.0',
+            'twisted[serial] >= 20.3.0',
             'pyasn1 >= 0.1.4',
         ],
         'tornado': [
diff --git a/test/conftest.py b/test/conftest.py
index 748fd4b7a..932e8124c 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -1,3 +1,8 @@
-from pymodbus.compat import IS_PYTHON3, PYTHON_VERSION
-if not IS_PYTHON3 or IS_PYTHON3 and PYTHON_VERSION.minor < 7:
-    collect_ignore = ["test_server_asyncio.py"]
+from pymodbus.compat import PYTHON_VERSION
+if PYTHON_VERSION < (3,):
+    # These files use syntax introduced between Python 2 and our lowest
+    # supported Python 3 version.  We just won't run these tests in Python 2.
+    collect_ignore = [
+        "test_client_async_asyncio.py",
+        "test_server_asyncio.py",
+    ]
diff --git a/tox.ini b/tox.ini
index 909d6a74d..91a573e7a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,12 +4,36 @@
 # directory.
 
 [tox]
-envlist = py27, py35, py36, py37, pypy
+envlist = py{27,py27,36,37,38,39,py36,py37}
 
 [testenv]
 deps = -r requirements-tests.txt
-commands = py.test {posargs}
-setenv = with_gmp=no
+commands =
+    pytest {posargs:--cov=pymodbus/ --cov-report=term-missing --cov-report=xml}
+setenv =
+    with_gmp=no
+
+[testenv:flake8]
+deps = -r requirements-checks.txt
+commands =
+    flake8
+
+[testenv:docs]
+allowlist_externals =
+    make
+deps = -r requirements-docs.txt
+commands =
+    make -C doc/ clean
+    make -C doc/ html
+
+[testenv:combined-coverage]
+allowlist_externals =
+    ls
+deps = -r requirements-coverage.txt
+commands =
+    ls -la coverage_reports
+    coverage combine coverage_reports
+    coverage report --fail-under=85 --ignore-errors
 
 [flake8]
 exclude = .tox