diff --git a/.github/workflows/docs-ci.yml b/.github/workflows/docs-ci.yml
index 18a44aa..8c2abfe 100644
--- a/.github/workflows/docs-ci.yml
+++ b/.github/workflows/docs-ci.yml
@@ -4,7 +4,7 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     strategy:
       max-parallel: 4
@@ -13,16 +13,13 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
 
-      - name: Give permission to run scripts
-        run: chmod +x ./docs/scripts/doc8_style_check.sh
-
       - name: Install Dependencies
         run:  pip install -e .[docs]
 
diff --git a/.github/workflows/pypi-release.yml b/.github/workflows/pypi-release.yml
index 22315ff..d2206c8 100644
--- a/.github/workflows/pypi-release.yml
+++ b/.github/workflows/pypi-release.yml
@@ -21,12 +21,12 @@ on:
 jobs:
   build-pypi-distribs:
     name: Build and publish library to PyPI
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v4
       - name: Set up Python
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v4
         with:
           python-version: 3.9
 
@@ -47,7 +47,7 @@ jobs:
     name: Create GH release
     needs:
       - build-pypi-distribs
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     steps:
       - name: Download built archives
@@ -67,7 +67,7 @@ jobs:
     name: Create PyPI release
     needs:
       - create-gh-release
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     steps:
       - name: Download built archives
@@ -78,6 +78,6 @@ jobs:
 
       - name: Publish to PyPI
         if: startsWith(github.ref, 'refs/tags')
-        uses: pypa/gh-action-pypi-publish@master
+        uses: pypa/gh-action-pypi-publish@release/v1
         with:
           password: ${{ secrets.PYPI_API_TOKEN }}
diff --git a/.gitignore b/.gitignore
index 78558e2..22d0741 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,7 @@
 *.py[cod]
 
 # virtualenv and other misc bits
-/src/*.egg-info
+*.egg-info
 /dist
 /build
 /bin
diff --git a/.readthedocs.yml b/.readthedocs.yml
index 1b71cd9..8ab2368 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -5,6 +5,17 @@
 # Required
 version: 2
 
+# Build in latest ubuntu/python
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
+# Build PDF & ePub
+formats:
+  - epub
+  - pdf
+
 # Where the Sphinx conf.py file is located
 sphinx:
    configuration: docs/source/conf.py
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..cc36c35
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (c) nexB Inc. and others. All rights reserved.
+# ScanCode is a trademark of nexB Inc.
+# SPDX-License-Identifier: Apache-2.0
+# See http://www.apache.org/licenses/LICENSE-2.0 for the license text.
+# See https://github.com/nexB/skeleton for support or download.
+# See https://aboutcode.org for more information about nexB OSS projects.
+#
+
+# Python version can be specified with `$ PYTHON_EXE=python3.x make conf`
+PYTHON_EXE?=python3
+VENV=venv
+ACTIVATE?=. ${VENV}/bin/activate;
+
+dev:
+	@echo "-> Configure the development envt."
+	./configure --dev
+
+isort:
+	@echo "-> Apply isort changes to ensure proper imports ordering"
+	${VENV}/bin/isort --sl -l 100 src tests setup.py
+
+black:
+	@echo "-> Apply black code formatter"
+	${VENV}/bin/black -l 100 src tests setup.py
+
+doc8:
+	@echo "-> Run doc8 validation"
+	@${ACTIVATE} doc8 --max-line-length 100 --ignore-path docs/_build/ --quiet docs/
+
+valid: isort black
+
+check:
+	@echo "-> Run pycodestyle (PEP8) validation"
+	@${ACTIVATE} pycodestyle --max-line-length=100 --exclude=.eggs,venv,lib,thirdparty,docs,migrations,settings.py,.cache .
+	@echo "-> Run isort imports ordering validation"
+	@${ACTIVATE} isort --sl --check-only -l 100 setup.py src tests . 
+	@echo "-> Run black validation"
+	@${ACTIVATE} black --check --check -l 100 src tests setup.py
+
+clean:
+	@echo "-> Clean the Python env"
+	./configure --clean
+
+test:
+	@echo "-> Run the test suite"
+	${VENV}/bin/pytest -vvs
+
+docs:
+	rm -rf docs/_build/
+	@${ACTIVATE} sphinx-build docs/ docs/_build/
+
+.PHONY: conf dev check valid black isort clean test docs
diff --git a/README.rst b/README.rst
index 70868e7..5e9731f 100644
--- a/README.rst
+++ b/README.rst
@@ -7,7 +7,7 @@ for Docker images, containers, root filesystems and virtual machine images.
 
 For Docker images, it can process layers and how these relate to each other as
 well as Dockerfiles.
- 
+
 **container-inspector** provides utilities to:
 
  - identify Docker images in a file system, its layers and the related metadata.
@@ -21,7 +21,7 @@ well as Dockerfiles.
    (implemented using a provided callable)
  - detect the "distro" of a rootfs of image using os-release files (and an
    extensive test suite for these)
- - detect the operating system, architecture and 
+ - detect the operating system, architecture and
 
 
 Quick start
@@ -32,12 +32,12 @@ Quick start
 - Check out a clone or download of container-inspector, then run: `./configure --dev`.
 - Then run `env/bin/container-inspector -h` for help.
 
- 
+
 Container image formats
 -----------------------
 
 container-inspector handles the formats of Docker images as created by the
-`docker save` command. There are three versions for this Docker image format. 
+`docker save` command. There are three versions for this Docker image format.
 The latest v1.2 is a minor update to v1.1.
 
 - v1.1 provides improved and richer metadata over v1.0 with a top level manifest.json
@@ -49,13 +49,13 @@ The latest v1.2 is a minor update to v1.1.
   format is no longer support in the latest version of container-inspector.
 
 - All V1.x formats use the same storage format for layers e.g the layer format V1.0
-  where each layer is stored in a sub-directories named after the layer id. 
-  Each of this directories contains a "layer.tar" tarball with the layer payload, 
+  where each layer is stored in a sub-directories named after the layer id.
+  Each of this directories contains a "layer.tar" tarball with the layer payload,
   a "json" JSON metadata file describing the layer and a "VERSION" file describing
   the layer format version. Each tarball represents a slice or diff of the image
   root file system using the AUFS conventions.
 
-At runtime, in a sequence of layers of an image, each root filesystem slice of a 
+At runtime, in a sequence of layers of an image, each root filesystem slice of a
 layer is "layered" on top of each other from the root bottom layer to the latest
 layer (or selected tagged layer) using a union file system (e.g. AUFS).
 In AUFS, any file or directory prefixed with .wh. are "white outs" files deleting
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 8640559..c4ada68 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -9,33 +9,49 @@ jobs:
 
     - template: etc/ci/azure-posix.yml
       parameters:
-          job_name: ubuntu18_cpython
-          image_name: ubuntu-18.04
-          python_versions: ['3.7', '3.8', '3.9', '3.10']
+          job_name: ubuntu20_cpython
+          image_name: ubuntu-20.04
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
           test_suites:
               all: venv/bin/pytest -n 2 -vvs
 
     - template: etc/ci/azure-posix.yml
       parameters:
-          job_name: ubuntu20_cpython
-          image_name: ubuntu-20.04
-          python_versions: ['3.7', '3.8', '3.9', '3.10']
+          job_name: ubuntu22_cpython
+          image_name: ubuntu-22.04
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
           test_suites:
               all: venv/bin/pytest -n 2 -vvs
 
     - template: etc/ci/azure-posix.yml
       parameters:
-          job_name: macos1015_cpython
-          image_name: macos-10.15
-          python_versions: ['3.7', '3.8', '3.9', '3.10']
+          job_name: macos11_cpython
+          image_name: macOS-11
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
           test_suites:
               all: venv/bin/pytest -n 2 -vvs
 
     - template: etc/ci/azure-posix.yml
       parameters:
-          job_name: macos11_cpython
-          image_name: macos-11
-          python_versions: ['3.7', '3.8', '3.9', '3.10']
+          job_name: macos12_cpython
+          image_name: macOS-12
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
+          test_suites:
+              all: venv/bin/pytest -n 2 -vvs
+
+    - template: etc/ci/azure-posix.yml
+      parameters:
+          job_name: macos13_cpython
+          image_name: macOS-13
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
+          test_suites:
+              all: venv/bin/pytest -n 2 -vvs
+
+    - template: etc/ci/azure-posix.yml
+      parameters:
+          job_name: macos14_cpython
+          image_name: macOS-14
+          python_versions: ['3.8', '3.9', '3.10', '3.11', '3.12']
           test_suites:
               all: venv/bin/pytest -n 2 -vvs
 
diff --git a/configure b/configure
index 32e02f5..926a894 100755
--- a/configure
+++ b/configure
@@ -36,7 +36,7 @@ DOCS_REQUIREMENTS="--editable .[docs] --constraint requirements.txt"
 VIRTUALENV_DIR=venv
 
 # Cleanable files and directories to delete with the --clean option
-CLEANABLE="build venv"
+CLEANABLE="build dist venv .cache .eggs"
 
 # extra  arguments passed to pip
 PIP_EXTRA_ARGS=" "
diff --git a/configure.bat b/configure.bat
index 41547cc..5e95b31 100644
--- a/configure.bat
+++ b/configure.bat
@@ -34,7 +34,7 @@ set "DOCS_REQUIREMENTS=--editable .[docs] --constraint requirements.txt"
 set "VIRTUALENV_DIR=venv"
 
 @rem # Cleanable files and directories to delete with the --clean option
-set "CLEANABLE=build venv"
+set "CLEANABLE=build dist venv .cache .eggs"
 
 @rem # extra  arguments passed to pip
 set "PIP_EXTRA_ARGS= "
diff --git a/docs/Makefile b/docs/Makefile
index d0c3cbf..788b039 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -5,6 +5,7 @@
 # from the environment for the first two.
 SPHINXOPTS    ?=
 SPHINXBUILD   ?= sphinx-build
+SPHINXAUTOBUILD = sphinx-autobuild
 SOURCEDIR     = source
 BUILDDIR      = build
 
@@ -14,6 +15,13 @@ help:
 
 .PHONY: help Makefile
 
+# Run the development server using sphinx-autobuild
+docs:
+	@echo
+	@echo "Starting up the docs server..."
+	@echo
+	$(SPHINXAUTOBUILD) --port 8000 --watch ${SOURCEDIR} $(SOURCEDIR) "$(BUILDDIR)/html" $(SPHINXOPTS) $(O)
+
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
 %: Makefile
diff --git a/docs/make.bat b/docs/make.bat
index 6247f7e..4a3c1a4 100644
--- a/docs/make.bat
+++ b/docs/make.bat
@@ -7,11 +7,16 @@ REM Command file for Sphinx documentation
 if "%SPHINXBUILD%" == "" (
 	set SPHINXBUILD=sphinx-build
 )
+if "%SPHINXAUTOBUILD%" == "" (
+	set SPHINXAUTOBUILD=sphinx-autobuild
+)
 set SOURCEDIR=source
 set BUILDDIR=build
 
 if "%1" == "" goto help
 
+if "%1" == "docs" goto docs
+
 %SPHINXBUILD% >NUL 2>NUL
 if errorlevel 9009 (
 	echo.
@@ -28,6 +33,13 @@ if errorlevel 9009 (
 %SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
 goto end
 
+:docs
+@echo
+@echo Starting up the docs server...
+@echo
+%SPHINXAUTOBUILD% --port 8000 --watch %SOURCEDIR% %SOURCEDIR% %BUILDDIR%\html %SPHINXOPTS% %O%
+goto end
+
 :help
 %SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
 
diff --git a/docs/scripts/doc8_style_check.sh b/docs/scripts/doc8_style_check.sh
old mode 100644
new mode 100755
diff --git a/docs/source/_static/theme_overrides.css b/docs/source/_static/theme_overrides.css
index 9662d63..5863ccf 100644
--- a/docs/source/_static/theme_overrides.css
+++ b/docs/source/_static/theme_overrides.css
@@ -1,353 +1,26 @@
-body {
-    color: #000000;
-}
-
-p {
-    margin-bottom: 10px;
-}
-
-.wy-plain-list-disc, .rst-content .section ul, .rst-content .toctree-wrapper ul, article ul {
-    margin-bottom: 10px;
-}
-
-.custom_header_01 {
-    color: #cc0000;
-    font-size: 22px;
-    font-weight: bold;
-    line-height: 50px;
-}
-
-h1, h2, h3, h4, h5, h6 {
-    margin-bottom: 20px;
-    margin-top: 20px;
-}
-
-h5 {
-    font-size: 18px;
-    color: #000000;
-    font-style: italic;
-    margin-bottom: 10px;
-}
-
-h6 {
-    font-size: 15px;
-    color: #000000;
-    font-style: italic;
-    margin-bottom: 10px;
-}
-
-/* custom admonitions */
-/* success */
-.custom-admonition-success  .admonition-title {
-    color: #000000;
-    background: #ccffcc;
-    border-radius: 5px 5px 0px 0px;
-}
-div.custom-admonition-success.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #cccccc;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
-/* important */
-.custom-admonition-important  .admonition-title {
-    color: #000000;
-    background: #ccffcc;
-    border-radius: 5px 5px 0px 0px;
-    border-bottom: solid 1px #000000;
-}
-div.custom-admonition-important.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #cccccc;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
-/* caution */
-.custom-admonition-caution  .admonition-title {
-    color: #000000;
-    background: #ffff99;
-    border-radius: 5px 5px 0px 0px;
-    border-bottom: solid 1px #e8e8e8;
-}
-div.custom-admonition-caution.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #cccccc;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
-/* note */
-.custom-admonition-note  .admonition-title {
-    color: #ffffff;
-    background: #006bb3;
-    border-radius: 5px 5px 0px 0px;
-}
-div.custom-admonition-note.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #cccccc;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
-/* todo */
-.custom-admonition-todo  .admonition-title {
-    color: #000000;
-    background: #cce6ff;
-    border-radius: 5px 5px 0px 0px;
-    border-bottom: solid 1px #99ccff;
-}
-div.custom-admonition-todo.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #99ccff;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
-/* examples */
-.custom-admonition-examples  .admonition-title {
-    color: #000000;
-    background: #ffe6cc;
-    border-radius: 5px 5px 0px 0px;
-    border-bottom: solid 1px #d8d8d8;
-}
-div.custom-admonition-examples.admonition {
-    color: #000000;
-    background: #ffffff;
-    border: solid 1px #cccccc;
-    border-radius: 5px;
-    box-shadow: 1px 1px 5px 3px #d8d8d8;
-    margin: 20px 0px 30px 0px;
-}
-
+/* this is the container for the pages */
 .wy-nav-content {
     max-width: 100%;
-    padding-right: 100px;
-    padding-left: 100px;
-    background-color: #f2f2f2;
-}
-
-div.rst-content {
-    background-color: #ffffff;
-    border: solid 1px #e5e5e5;
-    padding: 20px 40px 20px 40px;
-}
-
-.rst-content .guilabel {
-    border: 1px solid #ffff99;
-    background: #ffff99;
-    font-size: 100%;
-    font-weight: normal;
-    border-radius: 4px;
-    padding: 2px 0px;
-    margin: auto 2px;
-    vertical-align: middle;
-}
-
-.rst-content kbd {
-    font-family: SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",Courier,monospace;
-    border: solid 1px #d8d8d8;
-    background-color: #f5f5f5;
-    padding: 0px 3px;
-    border-radius: 3px;
-}
-
-.wy-nav-content-wrap a {
-    color: #0066cc;
-    text-decoration: none;
-}
-.wy-nav-content-wrap a:hover {
-    color: #0099cc;
-    text-decoration: underline;
-}
-
-.wy-nav-top a {
-    color: #ffffff;
-}
-
-/* Based on numerous similar approaches e.g., https://github.com/readthedocs/sphinx_rtd_theme/issues/117 and https://rackerlabs.github.io/docs-rackspace/tools/rtd-tables.html -- but remove form-factor limits to enable table wrap on full-size and smallest-size form factors */
-.wy-table-responsive table td {
-    white-space: normal !important;
-}
-
-.rst-content table.docutils td,
-.rst-content table.docutils th {
-    padding: 5px 10px 5px 10px;
-}
-.rst-content table.docutils td p,
-.rst-content table.docutils th p {
-    font-size: 14px;
-    margin-bottom: 0px;
-}
-.rst-content table.docutils td p cite,
-.rst-content table.docutils th p cite {
-    font-size: 14px;
-    background-color: transparent;
-}
-
-.colwidths-given th {
-    border: solid 1px #d8d8d8 !important;
-}
-.colwidths-given td {
-    border: solid 1px #d8d8d8 !important;
-}
-
-/*handles single-tick inline code*/
-.wy-body-for-nav cite {
-    color: #000000;
-    background-color: transparent;
-    font-style: normal;
-    font-family: "Courier New";
-    font-size: 13px;
-    padding: 3px 3px 3px 3px;
-}
-
-.rst-content pre.literal-block, .rst-content div[class^="highlight"] pre, .rst-content .linenodiv pre {
-    font-family: SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",Courier,monospace;
-    font-size: 13px;
-    overflow: visible;
-    white-space: pre-wrap;
-    color: #000000;
-}
-
-.rst-content pre.literal-block, .rst-content div[class^='highlight'] {
-    background-color: #f8f8f8;
-    border: solid 1px #e8e8e8;
-}
-
-/* This enables inline code to wrap. */
-code, .rst-content tt, .rst-content code {
-    white-space: pre-wrap;
-    padding: 2px 3px 1px;
-    border-radius: 3px;
-    font-size: 13px;
-    background-color: #ffffff;
-}
-
-/* use this added class for code blocks attached to bulleted list items */
-.highlight-top-margin {
-    margin-top: 20px !important;
-}
-
-/* change color of inline code block */
-span.pre {
-    color: #e01e5a;
-}
-
-.wy-body-for-nav blockquote {
-    margin: 1em 0;
-    padding-left: 1em;
-    border-left: 4px solid #ddd;
-    color: #000000;
-}
-
-/* Fix the unwanted top and bottom padding inside a nested bulleted/numbered list */
-.rst-content .section ol p, .rst-content .section ul p {
-    margin-bottom: 0px;
-}
-
-/* add spacing between bullets for legibility */
-.rst-content .section ol li, .rst-content .section ul li {
-    margin-bottom: 5px;
-}
-
-.rst-content .section ol li:first-child, .rst-content .section ul li:first-child {
-    margin-top: 5px;
-}
-
-/* but exclude the toctree bullets */
-.rst-content .toctree-wrapper ul li, .rst-content .toctree-wrapper ul li:first-child {
+    padding: 0px 40px 0px 0px;
     margin-top: 0px;
-    margin-bottom: 0px;
 }
 
-/* remove extra space at bottom of multine list-table cell */
-.rst-content .line-block {
-    margin-left: 0px;
-    margin-bottom: 0px;
-    line-height: 24px;
+.wy-nav-content-wrap {
+    border-right: solid 1px;
 }
 
-/* fix extra vertical spacing in page toctree */
-.rst-content .toctree-wrapper ul li ul, article ul li ul {
-    margin-top: 0;
-    margin-bottom: 0;
-}
-
-/* this is used by the genindex added via layout.html (see source/_templates/) to sidebar toc */
-.reference.internal.toc-index {
-    color: #d9d9d9;
-}
-
-.reference.internal.toc-index.current {
-    background-color: #ffffff;
-    color: #000000;
-    font-weight: bold;
-}
-
-.toc-index-div {
-    border-top: solid 1px #000000;
-    margin-top: 10px;
-    padding-top: 5px;
-}
-
-.indextable ul li {
-    font-size: 14px;
-    margin-bottom: 5px;
-}
-
-/* The next 2 fix the poor vertical spacing in genindex.html (the alphabetized index) */
-.indextable.genindextable {
-    margin-bottom: 20px;
-}
-
-div.genindex-jumpbox {
-    margin-bottom: 10px;
-}
-
-/* rst image classes */
-
-.clear-both {
-    clear: both;
-  }
-
-.float-left {
-    float: left;
-    margin-right: 20px;
-}
-
-img {
-    border: solid 1px #e8e8e8;
-}
-
-/* These are custom and need to be defined in conf.py to access in all pages, e.g., '.. role:: red' */
-.img-title {
-    color: #000000;
-    /* neither padding nor margin works for vertical spacing bc it's a span -- line-height does, sort of */
-    line-height: 3.0;
-    font-style: italic;
-    font-weight: 600;
-}
-
-.img-title-para {
-    color: #000000;
-    margin-top: 20px;
-    margin-bottom: 0px;
-    font-style: italic;
-    font-weight: 500;
-}
-
-.red {
-    color: red;
+div.rst-content {
+    max-width: 1300px;
+    border: 0;
+    padding: 10px 80px 10px 80px;
+    margin-left: 50px;
+}
+
+@media (max-width: 768px) {
+    div.rst-content {
+        max-width: 1300px;
+        border: 0;
+        padding: 0px 10px 10px 10px;
+        margin-left: 0px;
+    }
 }
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 4a2ae62..ec42f9f 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -29,15 +29,28 @@
 # ones.
 extensions = [
     "sphinx.ext.intersphinx",
+    "sphinx_reredirects",
+    "sphinx_rtd_theme",
+    "sphinx_rtd_dark_mode",
+    "sphinx.ext.extlinks",
+    "sphinx_copybutton",
 ]
 
+
+# Redirects for olds pages
+# See https://documatt.gitlab.io/sphinx-reredirects/usage.html
+redirects = {}
+
 # This points to aboutcode.readthedocs.io
 # In case of "undefined label" ERRORS check docs on intersphinx to troubleshoot
 # Link was created at commit - https://github.com/nexB/aboutcode/commit/faea9fcf3248f8f198844fe34d43833224ac4a83
 
 intersphinx_mapping = {
     "aboutcode": ("https://aboutcode.readthedocs.io/en/latest/", None),
-    "scancode-workbench": ("https://scancode-workbench.readthedocs.io/en/develop/", None),
+    "scancode-workbench": (
+        "https://scancode-workbench.readthedocs.io/en/develop/",
+        None,
+    ),
 }
 
 
@@ -72,7 +85,9 @@
     "conf_py_path": "/docs/source/",  # path in the checkout to the docs root
 }
 
-html_css_files = ["_static/theme_overrides.css"]
+html_css_files = [
+    "theme_overrides.css",
+]
 
 
 # If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
@@ -95,3 +110,7 @@
 .. role:: img-title-para
 
 """
+
+# -- Options for LaTeX output -------------------------------------------------
+
+latex_elements = {"classoptions": ",openany,oneside"}
diff --git a/etc/scripts/README.rst b/etc/scripts/README.rst
index edf82e4..5e54a2c 100755
--- a/etc/scripts/README.rst
+++ b/etc/scripts/README.rst
@@ -21,7 +21,7 @@ Pre-requisites
     virtualenv or in the the main configured development virtualenv.
     These requireements need to be installed::
 
-        pip install --requirement etc/release/requirements.txt
+        pip install --requirement etc/scripts/requirements.txt
 
 TODO: we need to pin the versions of these tools
 
@@ -34,7 +34,7 @@ Scripts
 ~~~~~~~
 
 **gen_requirements.py**: create/update requirements files from currently
-  installed requirements. 
+  installed requirements.
 
 **gen_requirements_dev.py** does the same but can subtract the main requirements
   to get extra requirements used in only development.
@@ -50,7 +50,7 @@ The sequence of commands to run are:
 
     ./configure --clean
     ./configure
-    python etc/release/gen_requirements.py --site-packages-dir <path to site-packages dir>
+    python etc/scripts/gen_requirements.py --site-packages-dir <path to site-packages dir>
 
 * You can optionally install or update extra main requirements after the
   ./configure step such that these are included in the generated main requirements.
@@ -59,7 +59,7 @@ The sequence of commands to run are:
 
     ./configure --clean
     ./configure --dev
-    python etc/release/gen_requirements_dev.py --site-packages-dir <path to site-packages dir>
+    python etc/scripts/gen_requirements_dev.py --site-packages-dir <path to site-packages dir>
 
 * You can optionally install or update extra dev requirements after the
   ./configure step such that these are included in the generated dev
diff --git a/etc/scripts/fetch_thirdparty.py b/etc/scripts/fetch_thirdparty.py
index 89d17de..eedf05c 100644
--- a/etc/scripts/fetch_thirdparty.py
+++ b/etc/scripts/fetch_thirdparty.py
@@ -12,6 +12,7 @@
 import itertools
 import os
 import sys
+from collections import defaultdict
 
 import click
 
@@ -110,6 +111,39 @@
     is_flag=True,
     help="Use on disk cached PyPI indexes list of packages and versions and do not refetch if present.",
 )
+@click.option(
+    "--sdist-only",
+    "sdist_only",
+    type=str,
+    metavar="SDIST",
+    default=tuple(),
+    show_default=False,
+    multiple=True,
+    help="Package name(s) that come only in sdist format (no wheels). "
+         "The command will not fail and exit if no wheel exists for these names",
+)
+@click.option(
+    "--wheel-only",
+    "wheel_only",
+    type=str,
+    metavar="WHEEL",
+    default=tuple(),
+    show_default=False,
+    multiple=True,
+    help="Package name(s) that come only in wheel format (no sdist). "
+         "The command will not fail and exit if no sdist exists for these names",
+)
+@click.option(
+    "--no-dist",
+    "no_dist",
+    type=str,
+    metavar="DIST",
+    default=tuple(),
+    show_default=False,
+    multiple=True,
+    help="Package name(s) that do not come either in wheel or sdist format. "
+         "The command will not fail and exit if no distribution exists for these names",
+)
 @click.help_option("-h", "--help")
 def fetch_thirdparty(
     requirements_files,
@@ -122,6 +156,9 @@ def fetch_thirdparty(
     sdists,
     index_urls,
     use_cached_index,
+    sdist_only,
+    wheel_only,
+    no_dist,
 ):
     """
     Download to --dest THIRDPARTY_DIR the PyPI wheels, source distributions,
@@ -204,58 +241,62 @@ def fetch_thirdparty(
             )
             repos.append(repo)
 
-    wheels_fetched = []
-    wheels_not_found = []
-
-    sdists_fetched = []
-    sdists_not_found = []
+    wheels_or_sdist_not_found = defaultdict(list)
 
     for name, version in sorted(required_name_versions):
         nv = name, version
         print(f"Processing: {name} @ {version}")
         if wheels:
             for environment in environments:
+
                 if TRACE:
                     print(f"  ==> Fetching wheel for envt: {environment}")
-                fwfns = utils_thirdparty.download_wheel(
+
+                fetched = utils_thirdparty.download_wheel(
                     name=name,
                     version=version,
                     environment=environment,
                     dest_dir=dest_dir,
                     repos=repos,
                 )
-                if fwfns:
-                    wheels_fetched.extend(fwfns)
-                else:
-                    wheels_not_found.append(f"{name}=={version} for: {environment}")
+                if not fetched:
+                    wheels_or_sdist_not_found[f"{name}=={version}"].append(environment)
                     if TRACE:
                         print(f"      NOT FOUND")
 
-        if sdists:
+        if (sdists or
+            (f"{name}=={version}" in wheels_or_sdist_not_found and name in sdist_only)
+         ):
             if TRACE:
                 print(f"  ==> Fetching sdist: {name}=={version}")
+
             fetched = utils_thirdparty.download_sdist(
                 name=name,
                 version=version,
                 dest_dir=dest_dir,
                 repos=repos,
             )
-            if fetched:
-                sdists_fetched.append(fetched)
-            else:
-                sdists_not_found.append(f"{name}=={version}")
+            if not fetched:
+                wheels_or_sdist_not_found[f"{name}=={version}"].append("sdist")
                 if TRACE:
                     print(f"      NOT FOUND")
 
-    if wheels and wheels_not_found:
-        print(f"==> MISSING WHEELS")
-        for wh in wheels_not_found:
-            print(f"  {wh}")
+    mia = []
+    for nv, dists in wheels_or_sdist_not_found.items():
+        name, _, version = nv.partition("==")
+        if name in no_dist:
+            continue
+        sdist_missing = sdists and "sdist" in dists and not name in wheel_only
+        if sdist_missing:
+            mia.append(f"SDist missing: {nv} {dists}")
+        wheels_missing = wheels and any(d for d in dists if d != "sdist") and not name in sdist_only
+        if wheels_missing:
+            mia.append(f"Wheels missing: {nv} {dists}")
 
-    if sdists and sdists_not_found:
-        print(f"==> MISSING SDISTS")
-        for sd in sdists_not_found:
-            print(f"  {sd}")
+    if mia:
+        for m in mia:
+            print(m)
+        raise Exception(mia)
 
     print(f"==> FETCHING OR CREATING ABOUT AND LICENSE FILES")
     utils_thirdparty.fetch_abouts_and_licenses(dest_dir=dest_dir, use_cached_index=use_cached_index)
diff --git a/etc/scripts/gen_pypi_simple.py b/etc/scripts/gen_pypi_simple.py
index 03312ab..214d90d 100644
--- a/etc/scripts/gen_pypi_simple.py
+++ b/etc/scripts/gen_pypi_simple.py
@@ -118,7 +118,7 @@ def build_per_package_index(pkg_name, packages, base_url):
   <body>"""
     document.append(header)
 
-    for package in packages:
+    for package in sorted(packages, key=lambda p: p.archive_file):
         document.append(package.simple_index_entry(base_url))
 
     footer = """  </body>
@@ -141,8 +141,8 @@ def build_links_package_index(packages_by_package_name, base_url):
   <body>"""
     document.append(header)
 
-    for _name, packages in packages_by_package_name.items():
-        for package in packages:
+    for _name, packages in sorted(packages_by_package_name.items(), key=lambda i: i[0]):
+        for package in sorted(packages, key=lambda p: p.archive_file):
             document.append(package.simple_index_entry(base_url))
 
     footer = """  </body>
diff --git a/etc/scripts/requirements.txt b/etc/scripts/requirements.txt
index ebb404b..7c514da 100644
--- a/etc/scripts/requirements.txt
+++ b/etc/scripts/requirements.txt
@@ -8,4 +8,5 @@ pip
 setuptools
 twine
 wheel
-build
\ No newline at end of file
+build
+packvers
diff --git a/etc/scripts/utils_dejacode.py b/etc/scripts/utils_dejacode.py
index f28e247..c42e6c9 100644
--- a/etc/scripts/utils_dejacode.py
+++ b/etc/scripts/utils_dejacode.py
@@ -15,7 +15,7 @@
 import requests
 import saneyaml
 
-from packaging import version as packaging_version
+from packvers import version as packaging_version
 
 """
 Utility to create and retrieve package and ABOUT file data from DejaCode.
diff --git a/etc/scripts/utils_pip_compatibility_tags.py b/etc/scripts/utils_pip_compatibility_tags.py
index 5d5eb34..af42a0c 100644
--- a/etc/scripts/utils_pip_compatibility_tags.py
+++ b/etc/scripts/utils_pip_compatibility_tags.py
@@ -27,7 +27,7 @@
 
 import re
 
-from packaging.tags import (
+from packvers.tags import (
     compatible_tags,
     cpython_tags,
     generic_tags,
diff --git a/etc/scripts/utils_requirements.py b/etc/scripts/utils_requirements.py
index 7c99a33..0fc25a3 100644
--- a/etc/scripts/utils_requirements.py
+++ b/etc/scripts/utils_requirements.py
@@ -8,6 +8,8 @@
 # See https://github.com/nexB/skeleton for support or download.
 # See https://aboutcode.org for more information about nexB OSS projects.
 #
+
+import os
 import re
 import subprocess
 
diff --git a/etc/scripts/utils_thirdparty.py b/etc/scripts/utils_thirdparty.py
index 53f2d33..addf8e5 100644
--- a/etc/scripts/utils_thirdparty.py
+++ b/etc/scripts/utils_thirdparty.py
@@ -28,8 +28,8 @@
 from commoncode import fileutils
 from commoncode.hash import multi_checksums
 from commoncode.text import python_safe_name
-from packaging import tags as packaging_tags
-from packaging import version as packaging_version
+from packvers import tags as packaging_tags
+from packvers import version as packaging_version
 
 import utils_pip_compatibility_tags
 
@@ -115,10 +115,9 @@
 TRACE_ULTRA_DEEP = False
 
 # Supported environments
-PYTHON_VERSIONS = "36", "37", "38", "39", "310"
+PYTHON_VERSIONS = "37", "38", "39", "310"
 
 PYTHON_DOT_VERSIONS_BY_VER = {
-    "36": "3.6",
     "37": "3.7",
     "38": "3.8",
     "39": "3.9",
@@ -134,7 +133,6 @@ def get_python_dot_version(version):
 
 
 ABIS_BY_PYTHON_VERSION = {
-    "36": ["cp36", "cp36m", "abi3"],
     "37": ["cp37", "cp37m", "abi3"],
     "38": ["cp38", "cp38m", "abi3"],
     "39": ["cp39", "cp39m", "abi3"],
@@ -912,7 +910,7 @@ def load_pkginfo_data(self, dest_dir=THIRDPARTY_DIR):
         declared_license = [raw_data["License"]] + [
             c for c in classifiers if c.startswith("License")
         ]
-        license_expression = compute_normalized_license_expression(declared_license)
+        license_expression = get_license_expression(declared_license)
         other_classifiers = [c for c in classifiers if not c.startswith("License")]
 
         holder = raw_data["Author"]
@@ -1337,10 +1335,10 @@ def package_from_dists(cls, dists):
 
         For example:
         >>> w1 = Wheel(name='bitarray', version='0.8.1', build='',
-        ...    python_versions=['cp36'], abis=['cp36m'],
+        ...    python_versions=['cp38'], abis=['cp38m'],
         ...    platforms=['linux_x86_64'])
         >>> w2 = Wheel(name='bitarray', version='0.8.1', build='',
-        ...    python_versions=['cp36'], abis=['cp36m'],
+        ...    python_versions=['cp38'], abis=['cp38m'],
         ...    platforms=['macosx_10_9_x86_64', 'macosx_10_10_x86_64'])
         >>> sd = Sdist(name='bitarray', version='0.8.1')
         >>> package = PypiPackage.package_from_dists(dists=[w1, w2, sd])
@@ -2274,16 +2272,16 @@ def find_problems(
     check_about(dest_dir=dest_dir)
 
 
-def compute_normalized_license_expression(declared_licenses):
+def get_license_expression(declared_licenses):
     """
     Return a normalized license expression or None.
     """
     if not declared_licenses:
         return
     try:
-        from packagedcode import pypi
+        from packagedcode.licensing import get_only_expression_from_extracted_license
 
-        return pypi.compute_normalized_license(declared_licenses)
+        return get_only_expression_from_extracted_license(declared_licenses)
     except ImportError:
         # Scancode is not installed, clean and join all the licenses
         lics = [python_safe_name(l).lower() for l in declared_licenses]
diff --git a/requirements.txt b/requirements.txt
index 0d6b14a..1f69c27 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ html5lib==1.1
 idna==3.3
 importlib-metadata==4.12.0
 inflection==0.5.1
-intbitset==3.0.1
+intbitset==3.1.0
 isodate==0.6.1
 jaraco.functools==3.5.1
 javaproperties==0.8.1
diff --git a/setup.cfg b/setup.cfg
index 918a285..305722b 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -71,14 +71,20 @@ where = src
 testing =
     pytest >= 6, != 7.0.0
     pytest-xdist >= 2
-    aboutcode-toolkit >= 6.0.0
-    black
+    aboutcode-toolkit >= 7.0.2
+    pycodestyle >= 2.8.0
     twine
+    black
+    isort
 
 docs =
-    Sphinx >= 3.3.1
-    sphinx-rtd-theme >= 0.5.0
-    doc8 >= 0.8.1
+    Sphinx>=5.0.2
+    sphinx-rtd-theme>=1.0.0
+    sphinx-reredirects >= 0.1.2
+    doc8>=0.11.2
+    sphinx-autobuild
+    sphinx-rtd-dark-mode>=1.3.0
+    sphinx-copybutton
 
 
 [options.entry_points]
diff --git a/thirdparty/README.rst b/thirdparty/README.rst
deleted file mode 100644
index b31482f..0000000
--- a/thirdparty/README.rst
+++ /dev/null
@@ -1,2 +0,0 @@
-Put your Python dependency wheels to be vendored in this directory.
-