diff --git a/.github/workflows/ci-docs.yml b/.github/workflows/ci-docs.yml
index bd89d7fe..a493a152 100644
--- a/.github/workflows/ci-docs.yml
+++ b/.github/workflows/ci-docs.yml
@@ -17,12 +17,12 @@ jobs:
       - uses: actions/setup-python@v4
         with:
           python-version: 3.9
-      - uses: Gr1N/setup-poetry@v8
-      - name: Cache Python dependencies
-        uses: actions/cache@v3
-        with:
-          path: ~/.cache/pypoetry/virtualenvs
-          key: ${{ runner.os }}-poetry-${{ hashFiles('poetry.lock') }}
+      - name: Install Poetry
+          uses: snok/install-poetry@v1
+          with:
+            version: "1.8.3"         # pin a known-good version instead of "latest"
+            virtualenvs-create: true
+            virtualenvs-in-project: true
       - name: Install python dependencies
         run: poetry install
       - name: Build and deploy docs
diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index acdc89be..bfb07625 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -16,11 +16,16 @@ jobs:
         - uses: actions/setup-python@v5
           with:
             python-version: ${{ matrix.python_version }}
-        - uses: Gr1N/setup-poetry@v9
+        - name: Install Poetry
+          uses: snok/install-poetry@v1
+          with:
+            version: "1.8.3"         # pin a known-good version instead of "latest"
+            virtualenvs-create: true
+            virtualenvs-in-project: true
         - name: Cache Python dependencies
           uses: actions/cache@v4
           with:
-            path: ~/.cache/pypoetry/virtualenvs
+            path: .venv
             key: ${{ runner.os }}-poetry-${{ hashFiles('poetry.lock') }}
 
         - name: Install python dependencies
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 482075af..22b4d02c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,12 +10,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 #### Changed
 
+- Update github actions installation procedures to use a maintained poetry installer [#623](https://github.com/askap-vast/vast-tools/pull/623)
+- Pin mkdocs-material to a sensible version [#623](https://github.com/askap-vast/vast-tools/pull/623)
+
 #### Fixed
 
 #### Removed
 
 #### List of PRs
 
+- Update github actions installation procedures to use a maintained poetry installer and pin mkdocs-material to a sensible version: fix, docs: [#623](https://github.com/askap-vast/vast-tools/pull/623)
 
 ## [3.3.0](https://github.com/askap-vast/vast-tools/releases/v3.3.0) (2026-07-20)
 
diff --git a/poetry.lock b/poetry.lock
index e33180dc..10bef171 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -3081,13 +3081,13 @@ pytz = ">=2025.1"
 
 [[package]]
 name = "mkdocs-material"
-version = "9.6.10"
+version = "9.6.9"
 description = "Documentation that simply works"
 optional = false
 python-versions = ">=3.8"
 files = [
-    {file = "mkdocs_material-9.6.10-py3-none-any.whl", hash = "sha256:36168548df4e2ddeb9a334ddae4ab9c388ccfea4dd50ffee657d22b93dcb1c3e"},
-    {file = "mkdocs_material-9.6.10.tar.gz", hash = "sha256:25a453c1f24f34fcf1f53680c03d2c1421b52ce5247f4468153c87a70cd5f1fc"},
+    {file = "mkdocs_material-9.6.9-py3-none-any.whl", hash = "sha256:6e61b7fb623ce2aa4622056592b155a9eea56ff3487d0835075360be45a4c8d1"},
+    {file = "mkdocs_material-9.6.9.tar.gz", hash = "sha256:a4872139715a1f27b2aa3f3dc31a9794b7bbf36333c0ba4607cf04786c94f89c"},
 ]
 
 [package.dependencies]
@@ -5603,4 +5603,4 @@ type = ["pytest-mypy"]
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.8.0,<3.11"
-content-hash = "009a02ae96d40032edf2ed953c4f504cb7ef716542a5fdfa12644fb99e31979a"
+content-hash = "29c409bdcc944ac8b0f95b722f82813c08f60c4f5608aab0d9d6aa962c6c13c2"
diff --git a/pyproject.toml b/pyproject.toml
index 6f9912fb..9f197a24 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,6 +37,7 @@ svgpath2mpl = "^1.0.0"
 setuptools = "^70.0.0"
 pydantic = "<2.0.0"
 jplephem = "^2.23"
+mkdocs-material = "<9.6.10"
 
 [tool.poetry.group.dev.dependencies]
 ipdb = "^0.13.6"