diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index b5e5a78f221..4cb3a750e4e 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -122,6 +122,18 @@ jobs:
           # Just Python 3.9 with default settings.
           - python-version: '3.9'
 
+          # Oldest macOS and olders Python supported versions.
+          # We pin a specific Python micro release due to a TK library bug.
+          # https://github.com/actions/setup-python/issues/402#issuecomment-1156015780
+          - python-version: '3.7.12'
+            runs-on: 'macos-10.15'
+            job-name: 'macos-10-default-tests'
+
+          # Newest macOS and newest Python supported versions.
+          - python-version: '3.10'
+            runs-on: 'macos-12'
+            job-name: 'macos-12-default-tests'
+
           # Windows, minimum Python version with select reactor.
           - python-version: '3.7'
             runs-on: 'windows-2022'
@@ -225,7 +237,7 @@ jobs:
     # If one of the above steps fails, fire up tmate for remote debugging.
     # This is fired for manual trigger or via the environment variable.
     - name: Tmate debug session
-      if: ${{ !cancelled() && (env.TMATE_DEBUG == 'yes' || github.event_name == 'workflow_dispatch' && inputs.debug_enabled ) }}
+      if: ${{ failure() && (env.TMATE_DEBUG == 'yes' || github.event_name == 'workflow_dispatch' && inputs.debug_enabled ) }}
       uses: mxschmitt/action-tmate@v3
       with:
         limit-access-to-actor: true
diff --git a/azure-pipelines/macos_test_jobs.yml b/azure-pipelines/macos_test_jobs.yml
deleted file mode 100644
index 0dd96a51f66..00000000000
--- a/azure-pipelines/macos_test_jobs.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-#
-# This is just a template, and not a main pipeline definition.
-#
-parameters:
-- name: imageName
-  type: string
-  default: 'macOS-latest'
-# Must be a mapping of id-suitable-name -> actual version number with dot
-- name: pythonVersions
-  type: object
-
-
-jobs:
-- ${{ each pyver in parameters.pythonVersions }}:
-  - job: ${{ format('macos_{0}', pyver.key) }}
-    displayName: ${{ format('MacOS Py{0}', pyver.value) }}
-    pool:
-      vmImage: ${{ parameters.imageName }}
-    steps:
-    - template: 'run_test_steps.yml'
-      parameters:
-        platform: macos
-        pythonVersion: ${{ pyver.value }}
diff --git a/azure-pipelines/run_test_steps.yml b/azure-pipelines/run_test_steps.yml
deleted file mode 100644
index 039d2c7dbe7..00000000000
--- a/azure-pipelines/run_test_steps.yml
+++ /dev/null
@@ -1,86 +0,0 @@
-#
-# This is just a template, and not a main pipeline definition.
-#
-parameters:
-
-- name: platform
-  type: string
-  values:
-  - macos
-  - windows
-
-- name: pythonVersion
-  type: string
-  values:
-  - '3.7'
-  - '3.8'
-  - '3.9'
-  - '3.10'
-
-- name: windowsReactor
-  type: string
-  default: select
-  values:
-  - select
-  - iocp
-
-- name: allowFailure
-  type: boolean
-  default: false
-
-steps:
-- checkout: self
-  clean: true
-  # A minimum depth of 2 is required, as the HEAD is the auto-merge commit
-  # and we need the last commit from the PR to report the coverage.
-  fetchDepth: 2
-
-- task: UsePythonVersion@0
-  displayName: "Use Python ${{ parameters.pythonVersion }}"
-  inputs:
-    versionSpec: "${{ parameters.pythonVersion }}"
-
-- script: |
-   python --version
-   python -c "import sys; print(sys.prefix)"
-   python -c "import sys; print(sys.exec_prefix)"
-   python -c "import sys; print(sys.executable)"
-   python -c "import struct; print(struct.calcsize('P') * 8)"
-   python -c "print('\nENVIRONMENT VARIABLES\n=====================\n\n')"
-   python -c "import os; [ print(e,v) for (e,v) in os.environ.items() ]"
-  displayName: 'Get Python Information'
-
-- script: 'python -m pip install -U pip setuptools tox coverage coveralls'
-  displayName: 'Update pip & install tox'
-
-- ${{ if eq(parameters.platform, 'macos') }}:
-  - script: 'python -m tox -e alldeps-withcov-posix'
-    displayName: 'Run tests'
-    continueOnError: ${{ parameters.allowFailure }}
-    env:
-      TRIAL_ARGS: "-j 4"
-
-- ${{ if eq(parameters.platform, 'windows') }}:
-  - script: 'python -m tox -e alldeps-withcov-windows'
-    displayName: 'Run tests'
-    continueOnError: ${{ parameters.allowFailure }}
-    env:
-      TRIAL_ARGS: --reactor=${{ parameters.windowsReactor }}
-
-- bash: |
-    # sub-process coverage are generated in separate files so we combine them
-    # to get an unified coverage for the local run.
-    # The XML is generate to be used with 3rd party tools like diff-cover.
-    python -m coverage combine
-    python -m coverage xml -o coverage.xml -i
-    python -m coverage report
-
-  displayName: 'Prepare coverage'
-  condition: always()
-  continueOnError: true
-
-- bash: |
-    bash <(curl -s https://codecov.io/bash) -X search -X gcov -f coverage.xml -n "${{ parameters.platform }}-${{ parameters.pythonVersion }}"
-  displayName: 'Report to Codecov'
-  condition: always()
-  continueOnError: true
diff --git a/azure-pipelines/tests_pipeline.yml b/azure-pipelines/tests_pipeline.yml
deleted file mode 100644
index c07ac11b31c..00000000000
--- a/azure-pipelines/tests_pipeline.yml
+++ /dev/null
@@ -1,33 +0,0 @@
-#
-# This is the main pipeline enabled in Azure DevOps
-# To update the name of this file you will need admin access to Azure.
-#
-# If the status failed to be reported, check the logs at
-# https://dev.azure.com/twistedmatrix/twisted/_build?view=runs
-#
-# Click on the PR description for more details.
-# Don't clock on the icon from the "Stages" column
-#
-trigger:
-  batch: true
-  branches:
-    include:
-    - trunk
-
-pr:
-  branches:
-    include:
-    - trunk
-
-variables:
-  INFRASTRUCTURE: "AZUREPIPELINES"
-  TRIAL_REPORTER: "verbose"
-  CI: "true"
-
-jobs:
-
-# Keep MacOS to latest CPython that we support.
-- template: 'macos_test_jobs.yml'
-  parameters:
-    pythonVersions:
-      py39: "3.10"
diff --git a/src/twisted/newsfragments/11664.misc b/src/twisted/newsfragments/11664.misc
new file mode 100644
index 00000000000..e69de29bb2d