diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 197ee96..67e755d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,6 +17,7 @@ concurrency:
 
 env:
   FORCE_COLOR: 2
+  PIP_PROGRESS_BAR: off
 
 jobs:
   build:
@@ -25,10 +26,10 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest']
-        python: ['3.8', '3.9', '3.10', '3.11', '3.x']
+        python: ['3.10', '3.11', '3.12', '3']
         include:
           - os: ubuntu-22.04
-            python: '3.7'
+            python: '3.9'
           - os: 'macos-latest'
             python: '3.9'
     name: ${{ matrix.os }} py-${{ matrix.python }}
@@ -37,9 +38,13 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: mamba-org/setup-micromamba@v2
         with:
-          python-version: ${{ matrix.python }}
+          cache-environment: true
+          post-cleanup: 'all'
+          environment-name: isodatetime-build
+          create-args: >-
+            python=${{ matrix.python }}
 
       - name: Build
         uses: cylc/release-actions/build-python-package@v1
@@ -49,6 +54,7 @@ jobs:
       - name: Inspect
         run: |
           unzip -l dist/*.whl | tee files
+          set -x
           grep 'metomi/isodatetime/data.py' files
-          grep 'metomi_isodatetime.*.dist-info/LICENSE' files
-          # grep 'metomi/isodatetime/py.typed' files # (not yet added)
+          grep 'metomi_isodatetime.*.dist-info/licenses/LICENSE' files
+          grep 'metomi/isodatetime/py.typed' files
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8bc6b35..b0e96ed 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -20,7 +20,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
         coverage: [false]
         include:
           # Modify existing configurations:
@@ -30,13 +30,13 @@ jobs:
             tz: 'XXX-05:30'  # UTC+05:30
           # Add new configurations:
           - os: ubuntu-22.04
-            python-version: '3.7'
+            python-version: '3.9' # oldest supported version
             coverage: false
           - os: ubuntu-latest
             python-version: '3.x'
             coverage: true
           - os: macos-latest
-            python-version: '3.9'
+            python-version: '3.9' # oldest supported version
             coverage: false
     name: ${{ matrix.os }} py-${{ matrix.python-version }} ${{ matrix.tz }} ${{ matrix.coverage && '(coverage)' || '' }}
     env:
diff --git a/CHANGES.md b/CHANGES.md
index 1600da0..bd6d969 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,6 +10,8 @@ updated. Only the first match gets replaced, so it's fine to leave the old
 ones in. -->
 ## isodatetime 3.2.0 (<span actions:bind='release-date'>Upcoming</span>)
 
+Requires Python 3.9+
+
 ### Breaking changes
 
 [#234](https://github.com/metomi/isodatetime/pull/234):
diff --git a/pyproject.toml b/pyproject.toml
index b7f9820..af7c696 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,22 +24,20 @@ authors = [
     {name = "Met Office", email = "metomi@metoffice.gov.uk"}
 ]
 description = "Python ISO 8601 date time parser and data model/manipulation utilities"
-license = {text = "LGPLv3"}
+license = "LGPL-3.0-only"
 readme = "README.md"
 keywords = ["isodatetime", "datetime", "iso8601", "date", "time", "parser"]
-requires-python = ">=3.7"
+requires-python = ">=3.9"
 classifiers = [
     "Development Status :: 5 - Production/Stable",
     "Environment :: Other Environment",
     "Intended Audience :: Developers",
-    "License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)",
     "Operating System :: OS Independent",
-    "Programming Language :: Python :: 3.7",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3 :: Only",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Utilities"
@@ -82,7 +80,7 @@ test = [
     "pytest-cov",
     "pytest-xdist",
     "flake8",
-    'flake8-type-checking; python_version > "3.7"',
+    'flake8-type-checking',
     "bandit>=1.7.1",
 ]
 all = [