diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..8af810e
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,10 @@
+---
+version: 2.1
+orbs:
+  kitchen: sous-chefs/kitchen@2
+workflows:
+  danger:
+    jobs:
+      - kitchen/danger:
+          name: danger
+          context: Danger-Minimal
diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..6ed589e
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use chefworkstation
diff --git a/.github/workflows/branchcleanup.yml b/.github/workflows/branchcleanup.yml
deleted file mode 100644
index 2aa1e96..0000000
--- a/.github/workflows/branchcleanup.yml
+++ /dev/null
@@ -1,17 +0,0 @@
----
-name: Branch Cleanup
-# This workflow is triggered on all closed pull requests.
-# However the script does not do anything if a merge was not performed.
-on:
-  pull_request:
-    types: [closed]
-
-env:
-  NO_BRANCH_DELETED_EXIT_CODE: 0
-  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: jessfraz/branch-cleanup-action@master
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..58e0b08
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,89 @@
+---
+name: ci
+
+"on":
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  delivery:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
+      - name: Run Chef Delivery
+        uses: actionshub/chef-delivery@master
+        env:
+          CHEF_LICENSE: accept-no-persist
+
+  yamllint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
+      - name: Run yaml Lint
+        uses: actionshub/yamllint@master
+
+  mdl:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
+      - name: Run Markdown Lint
+        uses: actionshub/markdownlint@master
+
+  dokken:
+    needs: [mdl, yamllint, delivery]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os:
+          - 'amazonlinux-2'
+          - 'debian-9'
+          - 'debian-10'
+          - 'centos-7'
+          - 'centos-8'
+          - 'fedora-latest'
+          - 'ubuntu-1604'
+          - 'ubuntu-1804'
+          - 'ubuntu-2004'
+          - 'opensuse-leap-15'
+        suite:
+          - 'default'
+          - 'aliases'
+          - 'client'
+          - 'server'
+          - 'canonical'
+          - 'sasl-auth-none'
+          - 'sasl-auth-multiple'
+          - 'sasl-auth-one'
+      fail-fast: false
+
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
+      - name: Install Chef
+        uses: actionshub/chef-install@master
+      - name: Dokken
+        uses: actionshub/kitchen-dokken@master
+        env:
+          CHEF_LICENSE: accept-no-persist
+          KITCHEN_LOCAL_YAML: kitchen.dokken.yml
+        with:
+          suite: ${{ matrix.suite }}
+          os: ${{ matrix.os }}
+      - name: Print debug output on failure
+        if: failure()
+        run: |
+            set -x
+            sudo journalctl -l --since today
+            KITCHEN_LOCAL_YAML=kitchen.dokken.yml /usr/bin/kitchen exec ${{ matrix.suite }}-${{ matrix.os }} -c "journalctl -l"
+
+  final:
+    needs: [dokken]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
diff --git a/.github/workflows/delivery.yml b/.github/workflows/delivery.yml
deleted file mode 100644
index 4b5c467..0000000
--- a/.github/workflows/delivery.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: delivery
-
-on: [push, pull_request]
-
-jobs:
-  delivery:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - name: Check out code
-      uses: actions/checkout@master
-    - name: Run Chef Delivery
-      uses: actionshub/chef-delivery@master
-      env:
-        CHEF_LICENSE: accept-no-persist
\ No newline at end of file
diff --git a/.github/workflows/md-links.yml b/.github/workflows/md-links.yml
new file mode 100644
index 0000000..150e75c
--- /dev/null
+++ b/.github/workflows/md-links.yml
@@ -0,0 +1,19 @@
+---
+name: md-links
+
+"on":
+  pull_request:
+  push:
+    branches: [master]
+
+jobs:
+  md-links:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@master
+      - name: markdown-link-check
+        uses: gaurav-nelson/github-action-markdown-link-check@v1
+        with:
+          use-verbose-mode: "yes"
+          folder-path: "documentation"
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
new file mode 100644
index 0000000..0f33701
--- /dev/null
+++ b/.github/workflows/stale.yml
@@ -0,0 +1,28 @@
+---
+name: Mark stale issues and pull requests
+
+"on":
+  schedule:
+    - cron: "0 0 * * *"
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/stale@v3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          close-issue-message: >
+            Closing due to inactivity.
+            If this is still an issue please reopen or open another issue.
+            Alternatively drop by the #sous-chefs channel on the [Chef Community Slack](http://community-slack.chef.io/) and we'll be happy to help!
+            Thanks, Sous-Chefs.
+          days-before-close: 7
+          days-before-stale: 365
+          stale-issue-message: >
+            Marking stale due to inactivity.
+            Remove stale label or comment or this will be closed in 7 days.
+            Alternatively drop by the #sous-chefs channel on the [Chef Community Slack](http://community-slack.chef.io/) and we'll be happy to help!
+            Thanks, Sous-Chefs.
diff --git a/.gitignore b/.gitignore
index e6099d3..be3b9a8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,6 @@
 *.rbc
 .config
 InstalledFiles
-lib/bundler/man
 pkg
 test/tmp
 test/version_tmp
@@ -16,11 +15,11 @@ _Store
 *.bk
 *.bkup
 
-# editor temp files
+# editor files
 .idea
 .*.sw[a-z]
 
-# ruby/bundler files
+# ruby/bundler/rspec files
 .ruby-version
 .ruby-gemset
 .rvmrc
diff --git a/.mdlrc b/.mdlrc
new file mode 100644
index 0000000..9cc2c63
--- /dev/null
+++ b/.mdlrc
@@ -0,0 +1 @@
+rules "~MD013", "~MD024", "~MD025"
diff --git a/.overcommit.yml b/.overcommit.yml
new file mode 100644
index 0000000..1d27ed8
--- /dev/null
+++ b/.overcommit.yml
@@ -0,0 +1,20 @@
+---
+PreCommit:
+  TrailingWhitespace:
+    enabled: true
+  YamlLint:
+    enabled: true
+  Rspec:
+    enabled: true
+    required_executable: 'rspec'
+  Cookstyle:
+    enabled: true
+    required_executable: 'cookstyle'
+    command: ["cookstyle"]
+  Delivery:
+    enabled: true
+    required_executable: 'delivery'
+    flags: ['local', 'all']
+CommitMsg:
+  HardTabs:
+    enabled: true
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index bd65cf5..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,49 +0,0 @@
-addons:
-  apt:
-    sources:
-      - chef-current-xenial
-    packages:
-      - chef-workstation
-
-install: echo "skip bundle install"
-
-env:
-  - CHEF_LICENSE=accept
-
-branches:
-  only:
-    - master
-
-services: docker
-
-env:
-  matrix:
-    #  - INSTANCE=default-amazonlinux # package install times out
-  - INSTANCE=default-centos-6
-  - INSTANCE=default-centos-7
-  - INSTANCE=default-debian-9
-  - INSTANCE=default-debian-10
-  - INSTANCE=default-ubuntu-1604
-  - INSTANCE=default-ubuntu-1804
-    #- INSTANCE=canonical-amazonlinux
-  - INSTANCE=canonical-centos-6
-  - INSTANCE=canonical-centos-7
-  - INSTANCE=canonical-debian-9
-  - INSTANCE=canonical-debian-10
-  - INSTANCE=canonical-ubuntu-1604
-  - INSTANCE=canonical-ubuntu-1804
-
-before_script:
-  - sudo iptables -L DOCKER || ( echo "DOCKER iptables chain missing" ; sudo iptables -N DOCKER )
-  - eval "$(chef shell-init bash)"
-  - chef --version
-
-script: KITCHEN_LOCAL_YAML=kitchen.dokken.yml kitchen verify ${INSTANCE}
-
-matrix:
-  include:
-    - script:
-      - delivery local all
-      env:
-        - UNIT_AND_LINT=1
-        - CHEF_LICENSE=accept
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
new file mode 100644
index 0000000..cd77725
--- /dev/null
+++ b/.vscode/extensions.json
@@ -0,0 +1,7 @@
+{
+  "recommendations": [
+      "chef-software.chef",
+      "rebornix.ruby",
+      "editorconfig.editorconfig"
+  ]
+}
diff --git a/.yamllint b/.yamllint
new file mode 100644
index 0000000..2d69612
--- /dev/null
+++ b/.yamllint
@@ -0,0 +1,7 @@
+---
+extends: default
+rules:
+  line-length:
+    max: 256
+    level: warning
+  document-start: disable
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ae91d24..2bfec10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,38 @@ This file is used to list changes made in each version of the postfix cookbook.
 
 - Disabled SSLv3 by default
 
+## 5.4.1 - 2020-10-20
+
+- Ensure all postmap files are rebuilt immediately if needed
+
+## 5.4.0 - 2020-10-11
+
+### Changed
+
+- Sous Chefs Adoption
+- Update to use Sous Chefs GH workflow
+- Update README to sous-chefs
+- Update metadata.rb to Sous Chefs
+- Update test-kitchen to Sous Chefs
+
+### Added
+
+- Standardise files with files in sous-chefs/repo-management
+- Add Ubuntu 20.04 testing
+
+### Fixed
+
+- Cookstyle fixes
+- ChefSpec fixes
+- Yamllint fixes
+- MDL fixes
+- Fix OpenSUSE installation issues
+
+### Removed
+
+- Remove EL 6 testing
+- Remove Amazon Linux 1 testing
+
 ## 5.3.1 (2018-07-24)
 
 - Fixed sbin issue with Chef13
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 980c134..20b4adb 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -1 +1,3 @@
-Please refer to the Chef Community Code of Conduct at https://www.chef.io/code-of-conduct/
+# Community Guidelines
+
+This project follows the Chef Community Guidelines <https://docs.chef.io/community_guidelines.html>
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index cd21578..a946aea 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1 +1,4 @@
-Please refer to <https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD>
+# Contributing
+
+Please refer to
+[https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD](https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD)
diff --git a/Dangerfile b/Dangerfile
new file mode 100644
index 0000000..bc08b7a
--- /dev/null
+++ b/Dangerfile
@@ -0,0 +1,47 @@
+# Reference: http://danger.systems/reference.html
+
+# A pull request summary is required. Add a description of the pull request purpose.
+# Changelog must be updated for each pull request that changes code.
+# Warnings will be issued for:
+#    Pull request with more than 400 lines of code changed
+#    Pull reqest that change more than 5 lines without test changes
+# Failures will be issued for:
+#    Pull request without summary
+#    Pull requests with code changes without changelog entry
+
+def code_changes?
+  code = %w(libraries attributes recipes resources files templates)
+  code.each do |location|
+    return true unless git.modified_files.grep(/#{location}/).empty?
+  end
+  false
+end
+
+def test_changes?
+  tests = %w(spec test kitchen.yml kitchen.dokken.yml)
+  tests.each do |location|
+    return true unless git.modified_files.grep(/#{location}/).empty?
+  end
+  false
+end
+
+failure 'Please provide a summary of your Pull Request.' if github.pr_body.length < 10
+
+warn 'This is a big Pull Request.' if git.lines_of_code > 400
+
+warn 'This is a Table Flip.' if git.lines_of_code > 2000
+
+# Require a CHANGELOG entry for non-test changes.
+if !git.modified_files.include?('CHANGELOG.md') && code_changes?
+  failure 'Please include a CHANGELOG entry.'
+end
+
+# Require Major Minor Patch version labels
+unless github.pr_labels.grep /minor|major|patch/i
+  warn 'Please add a release label to this pull request'
+end
+
+# A sanity check for tests.
+if git.lines_of_code > 5 && code_changes? && !test_changes?
+  warn 'This Pull Request is probably missing tests.'
+end
diff --git a/README.md b/README.md
index b01c173..0be8eb1 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,19 @@
 # postfix Cookbook
 
-[![Build Status](https://travis-ci.org/chef-cookbooks/postfix.svg?branch=master)](https://travis-ci.org/chef-cookbooks/postfix) [![Cookbook Version](https://img.shields.io/cookbook/v/postfix.svg)](https://supermarket.chef.io/cookbooks/postfix)
+[![Cookbook Version](https://img.shields.io/cookbook/v/postfix.svg)](https://supermarket.chef.io/cookbooks/postfix)
+[![CI State](https://github.com/sous-chefs/postfix/workflows/ci/badge.svg)](https://github.com/sous-chefs/postfix/actions?query=workflow%3Aci)
+[![OpenCollective](https://opencollective.com/sous-chefs/backers/badge.svg)](#backers)
+[![OpenCollective](https://opencollective.com/sous-chefs/sponsors/badge.svg)](#sponsors)
+[![License](https://img.shields.io/badge/License-Apache%202.0-green.svg)](https://opensource.org/licenses/Apache-2.0)
 
 Installs and configures postfix for client or outbound relayhost, or to do SASL authentication.
 
 On RHEL-family systems, sendmail will be replaced with postfix.
 
+## Maintainers
+
+This cookbook is maintained by the Sous Chefs. The Sous Chefs are a community of Chef cookbook maintainers working together to maintain important cookbooks. If you’d like to know more please visit [sous-chefs.org](https://sous-chefs.org/) or come chat with us on the Chef Community Slack in [#sous-chefs](https://chefcommunity.slack.com/messages/C2V7B88SF).
+
 ## Requirements
 
 ### Platforms
@@ -443,25 +451,27 @@ override_attributes(
 )
 ```
 
-## Maintainers
+## Contributors
 
-This cookbook is maintained by Chef's Community Cookbook Engineering team. Our goal is to improve cookbook quality and to aid the community in contributing to cookbooks. To learn more about our team, process, and design goals see our [team documentation](https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/COOKBOOK_TEAM.MD). To learn more about contributing to cookbooks like this see our [contributing documentation](https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD), or if you have general questions about this cookbook come chat with us in #cookbok-engineering on the [Chef Community Slack](http://community-slack.chef.io/)
+This project exists thanks to all the people who [contribute.](https://opencollective.com/sous-chefs/contributors.svg?width=890&button=false)
 
-## License
+### Backers
 
+Thank you to all our backers!
 
-**Copyright:** 2009-2017, Chef Software, Inc.
+![https://opencollective.com/sous-chefs#backers](https://opencollective.com/sous-chefs/backers.svg?width=600&avatarHeight=40)
 
-```
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
+### Sponsors
 
-    http://www.apache.org/licenses/LICENSE-2.0
+Support this project by becoming a sponsor. Your logo will show up here with a link to your website.
 
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-```
+![https://opencollective.com/sous-chefs/sponsor/0/website](https://opencollective.com/sous-chefs/sponsor/0/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/1/website](https://opencollective.com/sous-chefs/sponsor/1/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/2/website](https://opencollective.com/sous-chefs/sponsor/2/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/3/website](https://opencollective.com/sous-chefs/sponsor/3/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/4/website](https://opencollective.com/sous-chefs/sponsor/4/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/5/website](https://opencollective.com/sous-chefs/sponsor/5/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/6/website](https://opencollective.com/sous-chefs/sponsor/6/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/7/website](https://opencollective.com/sous-chefs/sponsor/7/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/8/website](https://opencollective.com/sous-chefs/sponsor/8/avatar.svg?avatarHeight=100)
+![https://opencollective.com/sous-chefs/sponsor/9/website](https://opencollective.com/sous-chefs/sponsor/9/avatar.svg?avatarHeight=100)
diff --git a/TESTING.md b/TESTING.md
index ca524ab..920e381 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -1,2 +1,3 @@
-Please refer to
-https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
+# Testing
+
+Please refer to [the community cookbook documentation on testing](https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD).
diff --git a/attributes/default.rb b/attributes/default.rb
index 0728944..4dacc00 100644
--- a/attributes/default.rb
+++ b/attributes/default.rb
@@ -109,6 +109,9 @@ when 'rhel'
   default['postfix']['cafile'] = '/etc/pki/tls/cert.pem'
 when 'amazon'
   default['postfix']['cafile'] = '/etc/pki/tls/cert.pem'
+when 'suse'
+  default['postfix']['main']['setgid_group'] = 'maildrop'
+  default['postfix']['main']['daemon_directory'] = '/usr/lib/postfix/bin'
 else
   default['postfix']['cafile'] = "#{node['postfix']['conf_dir']}/cacert.pem"
 end
diff --git a/chefignore b/chefignore
index 7cc7460..cc170ea 100644
--- a/chefignore
+++ b/chefignore
@@ -9,10 +9,7 @@ ehthumbs.db
 Icon?
 nohup.out
 Thumbs.db
-
-# SASS #
-########
-.sass-cache
+.envrc
 
 # EDITORS #
 ###########
@@ -26,10 +23,11 @@ Thumbs.db
 *.tmproj
 *~
 \#*
-mkmf.log
 REVISION
 TAGS*
 tmtags
+.vscode
+.editorconfig
 
 ## COMPILED ##
 ##############
@@ -42,22 +40,29 @@ tmtags
 *.so
 */rdoc/
 a.out
+mkmf.log
 
 # Testing #
 ###########
 .circleci/*
 .codeclimate.yml
+.delivery/*
 .foodcritic
 .kitchen*
+.mdlrc
+.overcommit.yml
 .rspec
 .rubocop.yml
 .travis.yml
 .watchr
+.yamllint
 azure-pipelines.yml
+Dangerfile
 examples/*
 features/*
 Guardfile
 kitchen.yml*
+mlc_config.json
 Procfile
 Rakefile
 spec/*
@@ -70,6 +75,7 @@ test/*
 .gitconfig
 .github/*
 .gitignore
+.gitkeep
 .gitmodules
 .svn
 */.bzr/*
@@ -95,12 +101,13 @@ Gemfile.lock
 Policyfile.rb
 Policyfile.lock.json
 
-# Cookbooks #
+# Documentation #
 #############
-CHANGELOG*
-CONTRIBUTING*
-TESTING*
 CODE_OF_CONDUCT*
+CONTRIBUTING*
+documentation/*
+TESTING*
+UPGRADING*
 
 # Vagrant #
 ###########
diff --git a/documentation/.gitkeep b/documentation/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/kitchen.dokken.yml b/kitchen.dokken.yml
index 33149ea..1d3b9e2 100644
--- a/kitchen.dokken.yml
+++ b/kitchen.dokken.yml
@@ -1,79 +1,73 @@
+---
 driver:
   name: dokken
-  privileged: true # because Docker and SystemD/Upstart
+  privileged: true  # because Docker and SystemD
   chef_version: <%= ENV['CHEF_VERSION'] || 'current' %>
-  chef_license: accept-no-persist
+  env: [CHEF_LICENSE=accept]
 
 transport:
   name: dokken
 
 provisioner:
   name: dokken
-  deprecations_as_errors: true
-
-verifier:
-  name: inspec
 
 platforms:
-- name: amazonlinux
-  driver:
-    image: dokken/amazonlinux
-    pid_one_command: /sbin/init
+  - name: amazonlinux-2
+    driver:
+      image: dokken/amazonlinux-2
+      pid_one_command: /usr/lib/systemd/systemd
 
-- name: amazonlinux-2
-  driver:
-    image: dokken/amazonlinux-2
-    pid_one_command: /usr/lib/systemd/systemd
+  - name: debian-9
+    driver:
+      image: dokken/debian-9
+      pid_one_command: /bin/systemd
+      intermediate_instructions:
+        - RUN /usr/bin/apt-get update
 
-- name: debian-9
-  driver:
-    image: dokken/debian-9
-    pid_one_command: /bin/systemd
-    intermediate_instructions:
-      - RUN /usr/bin/apt-get update
+  - name: debian-10
+    driver:
+      image: dokken/debian-10
+      pid_one_command: /bin/systemd
+      intermediate_instructions:
+        - RUN /usr/bin/apt-get update
 
-- name: debian-10
-  driver:
-    image: dokken/debian-10
-    pid_one_command: /bin/systemd
-    intermediate_instructions:
-      - RUN /usr/bin/apt-get update
+  - name: centos-7
+    driver:
+      image: dokken/centos-7
+      pid_one_command: /usr/lib/systemd/systemd
 
-- name: centos-6
-  driver:
-    image: dokken/centos-6
-    pid_one_command: /sbin/init
+  - name: centos-8
+    driver:
+      image: dokken/centos-8
+      pid_one_command: /usr/lib/systemd/systemd
 
-- name: centos-7
-  driver:
-    image: dokken/centos-7
-    pid_one_command: /usr/lib/systemd/systemd
+  - name: fedora-latest
+    driver:
+      image: dokken/fedora-latest
+      pid_one_command: /usr/lib/systemd/systemd
 
-- name: centos-8
-  driver:
-    image: dokken/centos-8
-    pid_one_command: /usr/lib/systemd/systemd
+  - name: ubuntu-16.04
+    driver:
+      image: dokken/ubuntu-16.04
+      pid_one_command: /bin/systemd
+      intermediate_instructions:
+        - RUN /usr/bin/apt-get update
 
-- name: fedora-latest
-  driver:
-    image: dokken/fedora-latest
-    pid_one_command: /usr/lib/systemd/systemd
+  - name: ubuntu-18.04
+    driver:
+      image: dokken/ubuntu-18.04
+      pid_one_command: /bin/systemd
+      intermediate_instructions:
+        - RUN /usr/bin/apt-get update
 
-- name: ubuntu-16.04
-  driver:
-    image: dokken/ubuntu-16.04
-    pid_one_command: /bin/systemd
-    intermediate_instructions:
-      - RUN /usr/bin/apt-get update
+  - name: ubuntu-20.04
+    driver:
+      image: dokken/ubuntu-20.04
+      pid_one_command: /bin/systemd
+      intermediate_instructions:
+        - RUN /usr/bin/apt-get update
 
-- name: ubuntu-18.04
-  driver:
-    image: dokken/ubuntu-18.04
-    pid_one_command: /bin/systemd
-    intermediate_instructions:
-      - RUN /usr/bin/apt-get update
-
-- name: opensuse-leap-15
-  driver:
-    image: dokken/opensuse-leap-15
-    pid_one_command: /bin/systemd
+  - name: opensuse-leap-15
+    driver:
+      image: dokken/opensuse-leap-15
+      pid_one_command: /bin/systemd
diff --git a/kitchen.yml b/kitchen.yml
index 61542e9..ebfff31 100644
--- a/kitchen.yml
+++ b/kitchen.yml
@@ -1,92 +1,89 @@
+---
 driver:
   name: vagrant
 
 provisioner:
   name: chef_zero
+  product_name: chef
+  enforce_idempotency: true
+  multiple_converge: 2
   deprecations_as_errors: true
-  chef_license: accept-no-persist
 
 verifier:
   name: inspec
 
 platforms:
-  - name: amazonlinux
-    driver_config:
-      box: mvbcoding/awslinux
   - name: amazonlinux-2
-  - name: centos-6
   - name: centos-7
   - name: centos-8
   - name: debian-9
-    run_list: apt::default
   - name: debian-10
-    run_list: apt::default
   - name: fedora-latest
   - name: opensuse-leap-15
   - name: ubuntu-16.04
-    run_list: apt::default
   - name: ubuntu-18.04
-    run_list: apt::default
+  - name: ubuntu-20.04
 
 suites:
-- name: default
-  run_list:
-  - recipe[postfix]
+  - name: default
+    run_list:
+      - recipe[postfix]
 
-- name: aliases
-  run_list:
-  - recipe[postfix::aliases]
+  - name: aliases
+    run_list:
+      - recipe[postfix::aliases]
 
-- name: client
-  run_list:
-  - recipe[postfix::client]
+  - name: client
+    run_list:
+      - recipe[postfix::client]
 
-- name: server
-  run_list:
-  - recipe[postfix::server]
+  - name: server
+    run_list:
+      - recipe[postfix::server]
 
-- name: canonical
-  run_list:
-  - recipe[postfix]
-  attributes:
-    postfix:
-      recipient_canonical_map_entries:
-        john: john@doe.com
+  - name: canonical
+    run_list:
+      - recipe[test::net_setup]
+      - recipe[postfix]
+    attributes:
+      postfix:
+        recipient_canonical_map_entries:
+          john: john@doe.com
 
-- name: sasl_auth_none
-  run_list:
-  - recipe[postfix::sasl_auth]
-  attributes:
-    postfix:
-      main:
-        relayhost: "localhost"
-        smtp_sasl_auth_enable: "yes"
+  - name: sasl_auth_none
+    run_list:
+      - recipe[postfix::sasl_auth]
+    attributes:
+      postfix:
+        main:
+          relayhost: "localhost"
+          smtp_sasl_auth_enable: "yes"
 
-- name: sasl_auth_multiple
-  run_list:
-  - recipe[postfix::sasl_auth]
-  attributes:
-    postfix:
-      main:
-        relayhost: "localhost"
-        smtp_sasl_auth_enable: "yes"
-      sasl:
-        relayhost1:
-          username: "kitchenuser"
-          password: "not-a-real-thing"
-        relayhost2:
-          username: "anotherkitchenuser"
-          password: "yet-not-a-real-thing"
+  - name: sasl_auth_multiple
+    run_list:
+      - recipe[postfix::sasl_auth]
+    attributes:
+      postfix:
+        main:
+          relayhost: "localhost"
+          smtp_sasl_auth_enable: "yes"
+        sasl:
+          relayhost1:
+            username: "kitchenuser"
+            password: "not-a-real-thing"
+          relayhost2:
+            username: "anotherkitchenuser"
+            password: "yet-not-a-real-thing"
 
-- name: sasl_auth_one
-  run_list:
-  - recipe[postfix::sasl_auth]
-  attributes:
-    postfix:
-      main:
-        relayhost: "localhost"
-        smtp_sasl_auth_enable: "yes"
-      sasl:
-        relayhost:
-          username: "kitchenuser"
-          password: "not-a-real-thing"
+  - name: sasl_auth_one
+    run_list:
+      - recipe[postfix::sasl_auth]
+    attributes:
+      postfix:
+        main:
+          relayhost: "localhost"
+          smtp_sasl_auth_enable: "yes"
+        sasl:
+          relayhost:
+            username: "kitchenuser"
+            password: "not-a-real-thing"
diff --git a/metadata.rb b/metadata.rb
index 2295ffe..9b7e829 100644
--- a/metadata.rb
+++ b/metadata.rb
@@ -1,14 +1,20 @@
-name 'postfix'
-maintainer 'Chef Software, Inc.'
-maintainer_email 'cookbooks@chef.io'
-license 'Apache-2.0'
-description 'Installs and configures postfix for client or outbound relayhost, or to do SASL auth'
-version '5.3.1'
+name              'postfix'
+maintainer        'Sous Chefs'
+maintainer_email  'help@sous-chefs.org'
+license           'Apache-2.0'
+description       'Installs and configures postfix for client or outbound relayhost, or to do SASL auth'
+version           '5.4.1'
+source_url        'https://github.com/sous-chefs/postfix'
+issues_url        'https://github.com/sous-chefs/postfix/issues'
+chef_version      '>= 12.15'
 
-%w(ubuntu debian redhat centos amazon oracle scientific smartos fedora freebsd).each do |os|
-  supports os
-end
-
-source_url 'https://github.com/chef-cookbooks/postfix'
-issues_url 'https://github.com/chef-cookbooks/postfix/issues'
-chef_version '>= 12.15'
+supports 'amazon'
+supports 'centos'
+supports 'debian'
+supports 'fedora'
+supports 'freebsd'
+supports 'oracle'
+supports 'redhat'
+supports 'scientific'
+supports 'smartos'
+supports 'ubuntu'
diff --git a/recipes/_common.rb b/recipes/_common.rb
index 069495b..260a9fb 100644
--- a/recipes/_common.rb
+++ b/recipes/_common.rb
@@ -2,7 +2,7 @@
 # Cookbook:: common
 # Recipe:: default
 #
-# Copyright:: 2009-2019, Chef Software, Inc.
+# Copyright:: 2009-2020, Chef Software, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,7 +19,14 @@
 
 include_recipe 'postfix::_attributes'
 
-package node['postfix']['packages']
+# use multi-package when we can
+if node['os'] == 'linux'
+  package node['postfix']['packages']
+else
+  node['postfix']['packages'].each do |pkg|
+    package pkg
+  end
+end
 
 package 'procmail' if node['postfix']['use_procmail']
 
@@ -35,6 +42,8 @@ when 'rhel', 'fedora', 'amazon'
     notifies :start, 'service[postfix]'
     not_if '/usr/bin/test /etc/alternatives/mta -ef /usr/sbin/sendmail.postfix'
   end
+when 'suse'
+  file '/var/adm/postfix.configured'
 when 'omnios'
   manifest_path = ::File.join(Chef::Config[:file_cache_path], 'manifest-postfix.xml')
 
@@ -122,11 +131,11 @@ unless node['postfix']['sender_canonical_map_entries'].empty?
     owner 'root'
     group node['root_group']
     mode '0644'
-    notifies :run, 'execute[update-postfix-sender_canonical]'
+    notifies :run, 'execute[update-postfix-sender_canonical]', :immediately
     notifies :reload, 'service[postfix]'
   end
 
-  node.normal['postfix']['main']['sender_canonical_maps'] = "hash:#{node['postfix']['conf_dir']}/sender_canonical" unless node['postfix']['main'].key?('sender_canonical_maps')
+  node.default['postfix']['main']['sender_canonical_maps'] = "hash:#{node['postfix']['conf_dir']}/sender_canonical" unless node['postfix']['main'].key?('sender_canonical_maps')
 end
 
 execute 'update-postfix-smtp_generic' do
@@ -139,11 +148,11 @@ unless node['postfix']['smtp_generic_map_entries'].empty?
     owner 'root'
     group node['root_group']
     mode '0644'
-    notifies :run, 'execute[update-postfix-smtp_generic]'
+    notifies :run, 'execute[update-postfix-smtp_generic]', :immediately
     notifies :reload, 'service[postfix]'
   end
 
-  node.normal['postfix']['main']['smtp_generic_maps'] = "hash:#{node['postfix']['conf_dir']}/smtp_generic" unless node['postfix']['main'].key?('smtp_generic_maps')
+  node.default['postfix']['main']['smtp_generic_maps'] = "hash:#{node['postfix']['conf_dir']}/smtp_generic" unless node['postfix']['main'].key?('smtp_generic_maps')
 end
 
 execute 'update-postfix-recipient_canonical' do
@@ -156,11 +165,11 @@ unless node['postfix']['recipient_canonical_map_entries'].empty?
     owner 'root'
     group node['root_group']
     mode '0644'
-    notifies :run, 'execute[update-postfix-recipient_canonical]'
+    notifies :run, 'execute[update-postfix-recipient_canonical]', :immediately
     notifies :reload, 'service[postfix]'
   end
 
-  node.normal['postfix']['main']['recipient_canonical_maps'] = "hash:#{node['postfix']['conf_dir']}/recipient_canonical" unless node['postfix']['main'].key?('recipient_canonical_maps')
+  node.default['postfix']['main']['recipient_canonical_maps'] = "hash:#{node['postfix']['conf_dir']}/recipient_canonical" unless node['postfix']['main'].key?('recipient_canonical_maps')
 end
 
 %w( main master ).each do |cfg|
diff --git a/recipes/access.rb b/recipes/access.rb
index d774347..cfe5dbd 100644
--- a/recipes/access.rb
+++ b/recipes/access.rb
@@ -23,5 +23,5 @@ end
 
 template node['postfix']['access_db'] do
   source 'access.erb'
-  notifies :run, 'execute[update-postfix-access]'
+  notifies :run, 'execute[update-postfix-access]', :immediately
 end
diff --git a/recipes/aliases.rb b/recipes/aliases.rb
index dcdbb4d..f8eec97 100644
--- a/recipes/aliases.rb
+++ b/recipes/aliases.rb
@@ -25,5 +25,5 @@ end
 
 template node['postfix']['aliases_db'] do
   source 'aliases.erb'
-  notifies :run, 'execute[update-postfix-aliases]'
+  notifies :run, 'execute[update-postfix-aliases]', :immediately
 end
diff --git a/recipes/client.rb b/recipes/client.rb
index d58fa20..b5009a6 100644
--- a/recipes/client.rb
+++ b/recipes/client.rb
@@ -39,6 +39,6 @@ else
   relayhost = results.map { |n| n['ipaddress'] }.first
 end
 
-node.normal['postfix']['main']['relayhost'] = "[#{relayhost}]#{relayhost_port}"
+node.default['postfix']['main']['relayhost'] = "[#{relayhost}]#{relayhost_port}"
 
 include_recipe 'postfix'
diff --git a/recipes/maps.rb b/recipes/maps.rb
index 4c853a5..a1b612f 100644
--- a/recipes/maps.rb
+++ b/recipes/maps.rb
@@ -1,4 +1,3 @@
-# encoding: utf-8
 # Copyright:: 2012-2019, Chef Software, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/recipes/relay_restrictions.rb b/recipes/relay_restrictions.rb
index de576e9..08aabcd 100644
--- a/recipes/relay_restrictions.rb
+++ b/recipes/relay_restrictions.rb
@@ -25,5 +25,5 @@ end
 
 template node['postfix']['relay_restrictions_db'] do
   source 'relay_restrictions.erb'
-  notifies :run, 'execute[update-postfix-relay-restrictions]'
+  notifies :run, 'execute[update-postfix-relay-restrictions]', :immediately
 end
diff --git a/recipes/sasl_auth.rb b/recipes/sasl_auth.rb
index 21ffa0b..bd9c18f 100644
--- a/recipes/sasl_auth.rb
+++ b/recipes/sasl_auth.rb
@@ -28,11 +28,7 @@ case node['platform_family']
 when 'debian'
   sasl_pkgs = %w(libsasl2-2 libsasl2-modules ca-certificates)
 when 'rhel'
-  sasl_pkgs = if node['platform_version'].to_i < 6
-                %w(cyrus-sasl cyrus-sasl-plain openssl)
-              else
-                %w(cyrus-sasl cyrus-sasl-plain ca-certificates)
-              end
+  sasl_pkgs = %w(cyrus-sasl cyrus-sasl-plain ca-certificates)
 when 'amazon'
   sasl_pkgs = %w(cyrus-sasl cyrus-sasl-plain ca-certificates)
 when 'fedora'
diff --git a/recipes/transports.rb b/recipes/transports.rb
index 7304712..5436ae6 100644
--- a/recipes/transports.rb
+++ b/recipes/transports.rb
@@ -25,5 +25,5 @@ end
 
 template node['postfix']['transport_db'] do
   source 'transport.erb'
-  notifies :run, 'execute[update-postfix-transport]'
+  notifies :run, 'execute[update-postfix-transport]', :immediately
 end
diff --git a/recipes/virtual_aliases.rb b/recipes/virtual_aliases.rb
index 8c79d87..7047807 100644
--- a/recipes/virtual_aliases.rb
+++ b/recipes/virtual_aliases.rb
@@ -23,6 +23,6 @@ end
 
 template node['postfix']['virtual_alias_db'] do
   source 'virtual_aliases.erb'
-  notifies :run, 'execute[update-postfix-virtual-alias]'
+  notifies :run, 'execute[update-postfix-virtual-alias]', :immediately
   notifies :restart, 'service[postfix]'
 end
diff --git a/recipes/virtual_aliases_domains.rb b/recipes/virtual_aliases_domains.rb
index 6c61152..3ded82d 100644
--- a/recipes/virtual_aliases_domains.rb
+++ b/recipes/virtual_aliases_domains.rb
@@ -23,6 +23,6 @@ end
 
 template node['postfix']['virtual_alias_domains_db'] do
   source 'virtual_aliases_domains.erb'
-  notifies :run, 'execute[update-postfix-virtual-alias-domains]'
+  notifies :run, 'execute[update-postfix-virtual-alias-domains]', :immediately
   notifies :restart, 'service[postfix]'
 end
diff --git a/spec/default_spec.rb b/spec/default_spec.rb
index 887b3a9..b6f6d50 100644
--- a/spec/default_spec.rb
+++ b/spec/default_spec.rb
@@ -5,9 +5,9 @@ describe 'postfix::default' do
     stub_command('/usr/bin/test /etc/alternatives/mta -ef /usr/sbin/sendmail.postfix').and_return(true)
   end
 
-  context 'on Centos 6' do
+  context 'on Centos 8' do
     cached(:chef_run) do
-      ChefSpec::SoloRunner.new(platform: 'centos', version: 6.9).converge(described_recipe)
+      ChefSpec::SoloRunner.new(platform: 'centos', version: '8').converge(described_recipe)
     end
 
     it '[COOK-4423] renders file main.cf with /etc/pki/tls/cert.pem' do
diff --git a/test/fixtures/cookbooks/test/recipes/net_setup.rb b/test/fixtures/cookbooks/test/recipes/net_setup.rb
new file mode 100644
index 0000000..e75459a
--- /dev/null
+++ b/test/fixtures/cookbooks/test/recipes/net_setup.rb
@@ -0,0 +1,3 @@
+sysctl 'net.ipv6.conf.lo.disable_ipv6' do
+  value 0
+end
diff --git a/test/integration/sasl_auth_multiple/serverspec/sasl_auth_multiple_spec.rb b/test/integration/sasl_auth_multiple/serverspec/sasl_auth_multiple_spec.rb
index 6210b79..c0c4979 100644
--- a/test/integration/sasl_auth_multiple/serverspec/sasl_auth_multiple_spec.rb
+++ b/test/integration/sasl_auth_multiple/serverspec/sasl_auth_multiple_spec.rb
@@ -1,4 +1,3 @@
-# encoding: utf-8
 # Copyright:: 2012-2019, Chef Software, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/test/integration/sasl_auth_one/serverspec/sasl_auth_one_spec.rb b/test/integration/sasl_auth_one/serverspec/sasl_auth_one_spec.rb
index 90b93d2..1e3cb3d 100644
--- a/test/integration/sasl_auth_one/serverspec/sasl_auth_one_spec.rb
+++ b/test/integration/sasl_auth_one/serverspec/sasl_auth_one_spec.rb
@@ -1,4 +1,3 @@
-# encoding: utf-8
 # Copyright:: 2012-2019, Chef Software, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");