diff --git a/.github/workflows/ci-docs.yml b/.github/workflows/ci-docs.yml
index d5a91f1c..8c03d643 100644
--- a/.github/workflows/ci-docs.yml
+++ b/.github/workflows/ci-docs.yml
@@ -1,7 +1,7 @@
 env:
   JULIA_CI: "true"
   PYTHONHASHSEED: "0"
-  PYTHON_VERSION: "3.8"
+  PYTHON_VERSION: "3.9"
 
 on:
   workflow_call:
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1202a371..6dcd3efb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-image: python:3.8
+image: python:3.9
 
 .cache-definitions:
   - &julia
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 215720ba..61092e36 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -14,7 +14,7 @@ repos:
       - id: check-useless-excludes
 
   - repo: https://github.com/ComPWA/policy
-    rev: 0.2.0
+    rev: 0.2.2
     hooks:
       - id: check-dev-files
         args:
diff --git a/README.md b/README.md
index 4d6836e3..2925d1a8 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,8 @@ Style checks are enforced with [Pre-commit](https://pre-commit.com). To activate
 pre-commit install
 ```
 
-For more information about local Python set-up, see [here](https://compwa-org.readthedocs.io/develop.html#local-set-up).
+> [!TIP]
+> For more information about the local Python developer environment, see [here](https://compwa.github.io/develop#local-set-up).
 
 This repository also contains Julia source code and Pluto notebooks. Julia can be downloaded [here](https://julialang.org/downloads). You then have to activate and instantiated the Julia environment provided in the [`julia`](./julia) folder. This can be done as follows from the root directory:
 
diff --git a/docs/index.md b/docs/index.md
index 872b3fa7..cbd72d24 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -136,7 +136,7 @@ hidden:
 ---
 JHEP <https://doi.org/10.1007/JHEP07(2023)228>
 arXiv:2301.07010 <https://arxiv.org/abs/2301.07010>
-ComPWA <https://compwa-org.readthedocs.io>
+ComPWA Project <https://compwa.github.io>
 GitHub repository <https://github.com/ComPWA/polarimetry>
 CERN GitLab (archived) <https://gitlab.cern.ch/polarimetry/Lc2pKpi>
 ```
diff --git a/docs/uncertainties.ipynb b/docs/uncertainties.ipynb
index 64488bc7..ddd6c49a 100644
--- a/docs/uncertainties.ipynb
+++ b/docs/uncertainties.ipynb
@@ -499,7 +499,7 @@
    "outputs": [],
    "source": [
     "def create_contour(phsp: DataSample) -> jax.Array:\n",
-    "    # See also https://compwa-org.rtfd.io/report/017.html\n",
+    "    # See also https://compwa.github.io/report/017\n",
     "    m0, m1, m2, m3, s1, s2 = sp.symbols(\"m(:4) sigma(1:3)\", nonnegative=True)\n",
     "    filter_expr = is_within_phasespace(\n",
     "        s1,\n",
diff --git a/environment.yml b/environment.yml
index e5dfa560..2964e36e 100644
--- a/environment.yml
+++ b/environment.yml
@@ -4,10 +4,10 @@ channels:
   - conda-forge
 dependencies:
   - juliaup
-  - python==3.8.*
+  - python==3.9.*
   - pip>=21.3 # pyproject.toml
   - pip:
-      - -c .constraints/py3.8.txt -e .[dev]
+      - -c .constraints/py3.9.txt -e .[dev]
 variables:
   PRETTIER_LEGACY_CLI: "1"
   PYTHONHASHSEED: 0