diff --git a/Makefile b/Makefile
index a3d114f..866fc9e 100644
--- a/Makefile
+++ b/Makefile
@@ -25,10 +25,10 @@ poller-once:
 	PYTHONPATH=src$${PYTHONPATH:+:$$PYTHONPATH} python -m kernel_ci_cloud_labs.pull_labs_poller --config $(CONFIG) --once
 
 install: build test
-	pip install -e .
+	python3.11 -m pip install -e .
 
 install-dev:
-	pip install -e ".[dev,test]"
+	python3.11 -m pip install -e ".[dev,test]"
 
 test:
 	python -m pytest tests/ -m "not integration"
diff --git a/QUICKSTART.md b/QUICKSTART.md
index 87e194b..2854137 100644
--- a/QUICKSTART.md
+++ b/QUICKSTART.md
@@ -19,11 +19,11 @@ provision AWS resources on its own. Before continuing, make sure the
 pipeline can run a job end-to-end. The full walkthrough lives in
 [`README.md`](README.md); the minimum steps are:
 
-1. **Install the package** in a venv — see
+1. **Install the package** in a venv — Python 3.11 required, see
    [README → Installation](README.md#installation):
    ```bash
-   python3 -m venv .venv && source .venv/bin/activate
-   pip install -e .
+   python3.11 -m venv .venv && source .venv/bin/activate
+   python3.11 -m pip install -e .
    ```
 2. **Configure AWS credentials** — see
    [README 1. Configure AWS Credentials](README.md#1-configure-aws-credentials).
diff --git a/README.md b/README.md
index a2f65f7..26a24ff 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,11 @@ This package provides the kernel-ci-cloud-runner python application as an entry
 
 ## Installation
 
+**Python 3.11 is required.** Older interpreters (including the `python3` shipped
+by Amazon Linux 2023, which is 3.9) are not supported — `pip install -e .` will
+refuse to run on them. On AL2023, install `python3.11 python3.11-pip
+python3.11-devel`; see [AWS_INSTALL.md](AWS_INSTALL.md) for the full host setup.
+
 Run the package in a virtual environment. We also provide the script "tests/test-in-venv.sh" to wrap these steps in en environment.
 
 If you do not have the code already, get your copy (git URL to be defined).
@@ -27,21 +32,21 @@ cd kernel-ci-cloud-labs
 Setup virtual environment:
 
 ```bash
-# Create virtual environment
-python3 -m venv .venv
+# Create virtual environment (Python 3.11 required)
+python3.11 -m venv .venv
 source .venv/bin/activate  # On Windows: .venv\Scripts\activate
 
 # Install package (runtime only - boto3)
-pip install -e .
+python3.11 -m pip install -e .
 
 # Optional: Install with dev dependencies (pytest, black, pylint, pre-commit, pytest-cov)
-pip install -e ".[dev]"
+python3.11 -m pip install -e ".[dev]"
 
 # Optional: Install with analysis dependencies (pandas, matplotlib, seaborn)
-pip install -e ".[analysis]"
+python3.11 -m pip install -e ".[analysis]"
 
 # Recommended: Install everything (dev + analysis)
-pip install -e ".[dev,analysis]"
+python3.11 -m pip install -e ".[dev,analysis]"
 
 # Optional: Install pre-commit hooks (only if you plan to commit code)
 pre-commit install
@@ -193,9 +198,9 @@ If not done already, set this up once:
 
 ```bash
 cd kernel-ci-cloud-labs
-python3 -m venv .venv
+python3.11 -m venv .venv
 source .venv/bin/activate
-pip install -e .
+python3.11 -m pip install -e .
 ```
 
 Activate the virtual environment. After this, `kernel-ci-cloud-runner` is available in your shell.
@@ -609,7 +614,7 @@ kernel-ci-cloud-runner aws analyze \
 
 This downloads all `benchmark-*.csv` files from S3, combines them, compares the two kernel versions, and generates regression plots (overall, x86_64, ARM64) in `analysis/data/{run_prefix}/`. Add `--upload-analysis` to upload the results back to S3.
 
-Requires the analysis dependencies: `pip install -e ".[analysis]"`
+Requires the analysis dependencies: `python3.11 -m pip install -e ".[analysis]"`
 
 ## Automated Triggering via EventBridge
 
diff --git a/pyproject.toml b/pyproject.toml
index 84ebb8d..3562609 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.black]
 line-length = 120
-target-version = ['py38', 'py39', 'py310', 'py311']
+target-version = ['py311']
 include = '\.pyi?$'
 extend-exclude = '''
 /(
diff --git a/setup.py b/setup.py
index 98be45f..8e39de9 100644
--- a/setup.py
+++ b/setup.py
@@ -27,7 +27,7 @@
     long_description=long_description,
     package_dir={"": "src"},
     packages=find_packages(where="src"),
-    python_requires=">=3.7",
+    python_requires=">=3.11",
     install_requires=[
         "boto3>=1.26.0",
     ],
diff --git a/src/kernel_ci_cloud_labs/pull_labs_poller.py b/src/kernel_ci_cloud_labs/pull_labs_poller.py
index d748b5a..47366aa 100644
--- a/src/kernel_ci_cloud_labs/pull_labs_poller.py
+++ b/src/kernel_ci_cloud_labs/pull_labs_poller.py
@@ -158,6 +158,46 @@ def write(self, timestamp: str) -> None:
 JobExecutor = Callable[[Dict[str, Any]], Tuple[List[Dict[str, Any]], Optional[str]]]
 
 
+_DEFAULT_EXECUTOR_PACKAGES = (
+    "kernel_ci_cloud_labs.providers",
+    "kernel_ci_cloud_labs.storage",
+    "kernel_ci_cloud_labs.auth",
+)
+
+
+def _validate_default_executor_deps() -> None:
+    """Eagerly import everything the default executor will need.
+
+    Called from PullLabsPoller.__init__ when no custom job_executor is
+    supplied, so a missing runtime dep (boto3, an un-installed package)
+    surfaces at startup instead of on the first event hours later. Raises
+    SystemExit with a single combined message listing every problem found.
+    """
+    from kernel_ci_cloud_labs.main import import_all_packages  # noqa: PLC0415
+
+    problems: List[str] = []
+    try:
+        import boto3  # noqa: F401,PLC0415
+    except ImportError as e:
+        problems.append(
+            f"boto3 import failed ({e}) — run: python3.11 -m pip install -e ."
+        )
+
+    for pkg in _DEFAULT_EXECUTOR_PACKAGES:
+        try:
+            import_all_packages(pkg)
+        except ImportError as e:
+            problems.append(f"{pkg} import failed: {e}")
+
+    if problems:
+        raise SystemExit(
+            "Default job executor dependencies are not installed:\n  - "
+            + "\n  - ".join(problems)
+            + "\nFix the install on this host, or pass a custom job_executor "
+              "to PullLabsPoller if you don't need the AWS pipeline."
+        )
+
+
 def _default_job_executor(run_config: Dict[str, Any]) -> Tuple[List[Dict[str, Any]], Optional[str]]:
     """Invoke the existing pipeline (provider-pluggable via registry).
 
@@ -175,11 +215,7 @@ def _default_job_executor(run_config: Dict[str, Any]) -> Tuple[List[Dict[str, An
     )
     from kernel_ci_cloud_labs.main import import_all_packages  # noqa: PLC0415
 
-    for pkg in [
-        "kernel_ci_cloud_labs.providers",
-        "kernel_ci_cloud_labs.storage",
-        "kernel_ci_cloud_labs.auth",
-    ]:
+    for pkg in _DEFAULT_EXECUTOR_PACKAGES:
         import_all_packages(pkg)
 
     auth_class = AUTH_REGISTRY[run_config["auth_credentials"]["auth_provider"]]
@@ -269,6 +305,9 @@ def __init__(
         self.job_executor: JobExecutor = job_executor or _default_job_executor
         self.base_config: Dict[str, Any] = config
 
+        if job_executor is None:
+            _validate_default_executor_deps()
+
     # -- Credential resolution -------------------------------------------
 
     @staticmethod
diff --git a/tests/test_pull_labs_poller.py b/tests/test_pull_labs_poller.py
index 2b323df..2962d31 100644
--- a/tests/test_pull_labs_poller.py
+++ b/tests/test_pull_labs_poller.py
@@ -12,6 +12,7 @@
 
 import pytest
 
+from kernel_ci_cloud_labs import pull_labs_poller as poller_mod
 from kernel_ci_cloud_labs.pull_labs_poller import (
     DEFAULT_FROM_TIMESTAMP,
     FileCursorStore,
@@ -20,6 +21,10 @@
     _parse_kcidb_rest,
 )
 
+# Capture the real validator at import time so a specific test can restore it
+# after the autouse fixture has stubbed it out.
+_REAL_VALIDATE_DEFAULT_EXECUTOR_DEPS = poller_mod._validate_default_executor_deps
+
 
 # ---------------------------------------------------------------------------
 # Helpers
@@ -37,6 +42,17 @@ def _clear_kernelci_env(monkeypatch):
         monkeypatch.delenv(var, raising=False)
 
 
+@pytest.fixture(autouse=True)
+def _skip_default_executor_deps_check(monkeypatch):
+    """Bypass the boto3/AWS-package import check the poller runs at startup.
+
+    The construction tests don't exercise the default executor and should not
+    depend on boto3 being installed in the test environment. Dedicated tests
+    for the validator itself temporarily restore the real function.
+    """
+    monkeypatch.setattr(poller_mod, "_validate_default_executor_deps", lambda: None)
+
+
 def _minimal_kc(**overrides):
     base = {
         "api_base_uri": "https://api.example/latest",
@@ -263,3 +279,46 @@ def test_empty_summary(self):
         rows, log = _extract_test_results({})
         assert rows == []
         assert log is None
+
+
+# ---------------------------------------------------------------------------
+# Default-executor dependency validation
+# ---------------------------------------------------------------------------
+
+
+class TestDefaultExecutorDepsValidation:
+    """Cover the startup check that runs when no custom job_executor is set."""
+
+    def test_missing_boto3_raises_systemexit(self, monkeypatch):
+        # Put back the real validator (autouse fixture stubbed it out).
+        monkeypatch.setattr(
+            poller_mod,
+            "_validate_default_executor_deps",
+            _REAL_VALIDATE_DEFAULT_EXECUTOR_DEPS,
+        )
+        # Force the boto3 import inside the validator to fail.
+        import builtins
+        real_import = builtins.__import__
+
+        def _fail_boto3(name, *args, **kwargs):
+            if name == "boto3":
+                raise ImportError("boto3 not installed (simulated)")
+            return real_import(name, *args, **kwargs)
+
+        monkeypatch.setattr(builtins, "__import__", _fail_boto3)
+        with pytest.raises(SystemExit) as ei:
+            PullLabsPoller(_minimal_kc())
+        assert "boto3" in str(ei.value)
+
+    def test_custom_executor_skips_validation(self, monkeypatch):
+        """Passing a custom executor must NOT trigger the boto3 check."""
+        called = {"validator": False}
+
+        def _fail_if_called():
+            called["validator"] = True
+            raise SystemExit("validator should not have been called")
+
+        monkeypatch.setattr(poller_mod, "_validate_default_executor_deps", _fail_if_called)
+        # Custom executor — validator must be skipped, no SystemExit.
+        PullLabsPoller(_minimal_kc(), job_executor=lambda cfg: ([], None))
+        assert called["validator"] is False