diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index f8e4031..a41643b 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -22,7 +22,7 @@ on:
 
 jobs:
   lint:
-    name: 'lint & typecheck & test (Python ${{ matrix.python }})'
+    name: "lint & typecheck & test (Python ${{ matrix.python }}${{ matrix.baseline && ', baseline deps' || '' }}${{ matrix.experimental && ', experimental' || '' }})"
     runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.experimental }}
     strategy:
@@ -33,24 +33,50 @@ jobs:
           - '3.11'
           - '3.12'
         experimental: [false]
+        baseline: [false]
         include:
           - python: '3.13'
+            baseline: false
             experimental: true
+          - python: '3.10'
+            baseline: true
+            experimental: false
     steps:
       - uses: actions/checkout@v4
+
+      - name: Install deps system-wide
+        if: success() && matrix.baseline
+        run: |
+          ./scripts/install-baseline-deps.sh
+          # give the Poetry environment access to the system-wide deps
+          # this has to be done before virtualenv creation
+          export POETRY_VIRTUALENVS_OPTIONS_SYSTEM_SITE_PACKAGES=true
+
       - name: Install Poetry
         run: pipx install poetry
       - uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python }}
           cache: poetry
-      - name: Install deps
+
+      - name: Install deps in the venv
+        if: success() && !matrix.baseline
         run: poetry install --with=dev
+      - name: Install only the dev tools in the venv
+        if: success() && matrix.baseline
+        run: poetry install --only=dev
+
       - name: Lint with ruff
         run: poetry run ruff check
       - name: Type-check with mypy
+        # it is rather cumbersome to work with ancient versions of deps that
+        # lack type annotations, so just rely on the CI job running with
+        # non-baseline deps
+        if: success() && !matrix.baseline
         run: poetry run mypy
       - name: Type-check with pyright
+        # same with pyright
+        if: success() && !matrix.baseline
         run: poetry run -- pyright --pythonversion ${{ matrix.python }}
       - name: Test with pytest
         run: poetry run pytest
diff --git a/poetry.lock b/poetry.lock
index 3a96a04..fa1cac0 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1033,4 +1033,4 @@ cffi = ["cffi (>=1.11)"]
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.10"
-content-hash = "9c530aa0b089259b1388da31f33c6d036dded373eed6f35672466f0e229ee667"
+content-hash = "e1e169e55bdc5d8536ba3b1c5fb2dc7b4c6a9fd1d5d8faf42dcad20ee3058b88"
diff --git a/pyproject.toml b/pyproject.toml
index c9610f0..33641c7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -87,7 +87,7 @@ mypy = "^1.9.0"
 pyright = "^1.1.389"
 pytest = "^8.2.2"
 ruff = "^0.8.1"
-typing-extensions = "^4.12.2"
+typing-extensions = ">=3.10.0.2"
 
 types-cffi = "^1.16.0.20240106"
 types-pygit2 = "^1.14.0.20240317"
diff --git a/ruyi/utils/ar.py b/ruyi/utils/ar.py
index 405b720..e2c2119 100644
--- a/ruyi/utils/ar.py
+++ b/ruyi/utils/ar.py
@@ -8,8 +8,8 @@
 
 
 class ArpyArchiveWrapper(arpy.Archive, AbstractContextManager["arpy.Archive"]):
-    """Compatibility context manager shim for arpy.Archive, for working across
-    arpy 1.x and 2.x."""
+    """Compatibility shim for arpy.Archive, for easy interop with both arpy 1.x
+    and 2.x."""
 
     def __init__(
         self,
@@ -38,3 +38,37 @@ def __exit__(
 
         # backport of arpy 2.x __exit__ implementation
         self.close()
+
+    def infolist(self) -> list[arpy.ArchiveFileHeader]:
+        if hasattr(super(), "infolist"):
+            return super().infolist()
+
+        # backport of arpy 2.x infolist()
+        self.read_all_headers()
+        return [
+            header
+            for header in self.headers
+            if header.type
+            in (
+                arpy.HEADER_BSD,
+                arpy.HEADER_NORMAL,
+                arpy.HEADER_GNU,
+            )
+        ]
+
+    def open(self, name: bytes | arpy.ArchiveFileHeader) -> arpy.ArchiveFileData:
+        if hasattr(super(), "open"):
+            return super().open(name)
+
+        # backport of arpy 2.x open()
+        if isinstance(name, bytes):
+            ar_file = self.archived_files.get(name)
+            if ar_file is None:
+                raise KeyError("There is no item named %r in the archive" % (name,))
+
+            return ar_file
+
+        if name not in self.headers:
+            raise KeyError("Provided header does not match this archive")
+
+        return arpy.ArchiveFileData(ar_obj=self, header=name)
diff --git a/scripts/install-baseline-deps.sh b/scripts/install-baseline-deps.sh
new file mode 100755
index 0000000..fc11915
--- /dev/null
+++ b/scripts/install-baseline-deps.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+
+set -e
+
+main() {
+    local pkglist=(
+        # Package versions provided by Ubuntu 22.04 LTS.
+        python3-arpy  # 1.1.1
+        python3-certifi  # 2020.6.20
+        python3-jinja2  # 3.0.3
+        python3-packaging  # 21.3
+        python3-pygit2  # 1.6.1
+        python3-yaml  # 5.4.1  # https://github.com/yaml/pyyaml/issues/724
+        python3-requests  # 2.25.1
+        python3-rich  # 11.2.0
+        python3-semver  # 2.10.2
+        python3-tomli  # 1.2.2
+        python3-tomlkit  # 0.9.2
+        python3-typing-extensions  # 3.10.0.2
+    )
+
+    export DEBIAN_FRONTEND=noninteractive
+    export DEBCONF_NONINTERACTIVE_SEEN=true
+    sudo apt-get update -qqy
+    sudo apt-get install -y "${pkglist[@]}"
+}
+
+main "$@"