diff --git a/README.md b/README.md
index bae9b4c0..834ac314 100644
--- a/README.md
+++ b/README.md
@@ -29,15 +29,22 @@ Lemonade and vLLM.
 
 | Platform | Prebuilt binary | Notes |
 |---|---|---|
-| Linux (x86_64) | Yes | Full support, including the live dashboard and both inference engines |
+| Linux (x86_64) | Yes | Ubuntu 24.04 or newer; full support, including the live dashboard and both inference engines |
 | Windows (x86_64) | Yes | CLI and Lemonade serving; no live dashboard or vLLM |
-| WSL2 (x86_64) | Yes (Linux binary) | Full support, including the live dashboard; see [docs/wsl.md](docs/wsl.md) for setup |
+| WSL2 (x86_64) | Yes (Linux binary) | Ubuntu 24.04 or newer; full support, including the live dashboard; see [docs/wsl.md](docs/wsl.md) for setup |
 | macOS | No | No official installer, release, CI, or QA coverage |
 
 Live dashboard telemetry requires Linux or WSL2 (see
 [Interactive interfaces](#interactive-interfaces)). vLLM serving is Linux/WSL2
 only (see [docs/vllm.md](docs/vllm.md)).
 
+The minimum supported Linux release, native or under WSL2, is Ubuntu 24.04. On
+other distributions the equivalent requirement is glibc 2.38 with
+`GLIBCXX_3.4.32`: that is what the Lemonade engine is linked against, and every
+published build of it needs those versions, so there is no older release to fall
+back to. Ubuntu 22.04 ships glibc 2.35 and cannot run it; Ubuntu 24.04 provides
+glibc 2.39 and `GLIBCXX_3.4.33`.
+
 > [!IMPORTANT]
 > **Tech Preview** -- This software is provided as-is, without warranty or
 > guarantee of stability. APIs, commands, and behavior may change without
diff --git a/docs/wsl.md b/docs/wsl.md
index 1b9a90a1..24a53679 100644
--- a/docs/wsl.md
+++ b/docs/wsl.md
@@ -14,7 +14,10 @@ virtual environments and ROCDXG (`librocdxg`).
 The AMD WSL path is:
 
 1. Windows 11 with the AMD Adrenalin WSL-capable driver.
-2. WSL2 with Ubuntu 24.04 or Ubuntu 22.04.
+2. WSL2 with Ubuntu 24.04 or newer. Ubuntu 22.04 is not supported: it ships
+   glibc 2.35, below the glibc 2.38 / `GLIBCXX_3.4.32` floor that every
+   published Lemonade embeddable requires, so the Lemonade engine cannot start
+   there. Ubuntu 24.04 provides glibc 2.39 and `GLIBCXX_3.4.33`.
 3. ROCDXG (`librocdxg`) installed inside WSL.
 4. A TheRock runtime installed by `rocm-cli` into a managed Python venv.
 
diff --git a/scripts/wsl_preflight.py b/scripts/wsl_preflight.py
index 436b0db2..042aab4e 100644
--- a/scripts/wsl_preflight.py
+++ b/scripts/wsl_preflight.py
@@ -258,11 +258,20 @@ def evaluate(
     sdk_headers = state.get("windows_sdk_headers") or []
 
     version_id = str(os_release.get("VERSION_ID") or "")
-    supported_ubuntu = os_release.get("ID") == "ubuntu" and version_id in {
-        "22.04",
-        "24.04",
-        "26.04",
-    }
+    # 22.04 is deliberately unsupported: its glibc 2.35 is below the glibc 2.38 /
+    # GLIBCXX_3.4.32 floor every published Lemonade embeddable is linked
+    # against, so the Lemonade engine cannot start on it. See docs/wsl.md.
+    version_parts = version_id.split(".")
+    ubuntu_version = None
+    if len(version_parts) == 2 and all(
+        part.isascii() and part.isdecimal() for part in version_parts
+    ):
+        ubuntu_version = (int(version_parts[0]), int(version_parts[1]))
+    supported_ubuntu = (
+        os_release.get("ID") == "ubuntu"
+        and ubuntu_version is not None
+        and ubuntu_version >= (24, 4)
+    )
     build_tools = all(
         tools.get(name) for name in ["git", "cmake", "gcc", "g++", "make"]
     )
@@ -270,7 +279,9 @@ def evaluate(
     checks = [
         Check("wsl", bool(state.get("is_wsl")), "WSL marker or /dev/dxg detected"),
         Check(
-            "ubuntu", supported_ubuntu, f"Ubuntu VERSION_ID={version_id or '<unknown>'}"
+            "ubuntu",
+            supported_ubuntu,
+            f"Ubuntu 24.04 or newer (VERSION_ID={version_id or '<unknown>'})",
         ),
         Check("dxg_device", bool(paths.get("/dev/dxg")), "/dev/dxg"),
         Check(
@@ -391,6 +402,28 @@ def self_test() -> None:
     checks = evaluate(ready_state, require_rocm_tools=False)
     assert all(check.ok for check in checks if check.required), checks
 
+    for version_id in ["24.04", "24.10", "25.04", "26.04", "28.04"]:
+        supported_state = json.loads(json.dumps(ready_state))
+        supported_state["os_release"]["VERSION_ID"] = version_id
+        checks = evaluate(supported_state, require_rocm_tools=False)
+        assert any(check.name == "ubuntu" and check.ok for check in checks), checks
+        assert all(check.ok for check in checks if check.required), checks
+
+    # 22.04 is below the Lemonade glibc floor, and malformed or unknown
+    # versions must fail closed rather than report an otherwise perfect host ready.
+    for version_id in ["22.04", "24.04.1", "unknown", ""]:
+        unsupported_state = json.loads(json.dumps(ready_state))
+        unsupported_state["os_release"]["VERSION_ID"] = version_id
+        checks = evaluate(unsupported_state, require_rocm_tools=False)
+        assert any(check.name == "ubuntu" and not check.ok for check in checks), checks
+        assert not all(check.ok for check in checks if check.required), checks
+
+    missing_version_state = json.loads(json.dumps(ready_state))
+    del missing_version_state["os_release"]["VERSION_ID"]
+    checks = evaluate(missing_version_state, require_rocm_tools=False)
+    assert any(check.name == "ubuntu" and not check.ok for check in checks), checks
+    assert not all(check.ok for check in checks if check.required), checks
+
 
 def main() -> int:
     parser = argparse.ArgumentParser(description=__doc__)