diff --git a/build_system/builder/release/tools/check_public_binary_release.py b/build_system/builder/release/tools/check_public_binary_release.py
index 84c4a865f..c6310feb1 100644
--- a/build_system/builder/release/tools/check_public_binary_release.py
+++ b/build_system/builder/release/tools/check_public_binary_release.py
@@ -731,7 +731,11 @@ def run_docker_binary_transition_smoke(
 chmod 0440 /etc/sudoers.d/capsemtest
 check_binary_versions() {{
   expected="$1"
+  # Each installed package is held to the binaries it owns: the older one
+  # predates capsem-router (it shipped capsem-port-router).
+  owned=$(dpkg -L capsem)
   for bin in {helpers}; do
+    printf '%s\n' "$owned" | grep -Fqx "/usr/bin/$bin" || continue
     su capsemtest -c "test -x \"\\$HOME/.capsem/bin/$bin\""
     su capsemtest -c "\"\\$HOME/.capsem/bin/$bin\" --version" | grep -F "$expected"
   done
diff --git a/build_system/builder/release/tools/release_installed_probe.py b/build_system/builder/release/tools/release_installed_probe.py
index f12e1cd02..d50b5b2d3 100644
--- a/build_system/builder/release/tools/release_installed_probe.py
+++ b/build_system/builder/release/tools/release_installed_probe.py
@@ -27,6 +27,21 @@
 )
 
 
+def packaged_host_binaries(deb: Path) -> tuple[str, ...]:
+    """The host binaries an exact package ships, in HOST_BINARIES order.
+
+    A transition installs an older package first, and binary sets change
+    between releases: 0.6.3 shipped capsem-port-router, not capsem-router.
+    Checking the current names against it failed on a binary that package
+    never had, so each installed package is held to its own payload.
+    """
+    shipped = {
+        Path(name).name
+        for name in deb_payload_files(deb, select=lambda name: Path(name).parent.as_posix().endswith("usr/bin"))
+    }
+    return tuple(binary for binary in HOST_BINARIES if binary in shipped)
+
+
 def packaged_manifest_metadata(deb: Path) -> dict[str, str]:
     """Return the future polling identity declared by an exact package.
 
@@ -114,7 +129,10 @@ def exact_installed_probe_shell(evidence_dir: Path) -> str:
 }}
 check_binary_versions() {{
   expected="$1"
-  for binary in {" ".join(HOST_BINARIES)}; do
+  artifact="$2"
+  binaries=$({shlex.quote(sys.executable)} -c 'import sys; from pathlib import Path; from capsem_builder.release.tools.release_installed_probe import packaged_host_binaries; print(" ".join(packaged_host_binaries(Path(sys.argv[1]))))' "$artifact")
+  test -n "$binaries"
+  for binary in $binaries; do
     test -x "$CAPSEM_HOME_DIR/bin/$binary"
     if [ "$binary" = capsem ]; then
       "$CAPSEM_HOME_DIR/bin/$binary" version
@@ -134,7 +152,7 @@ def exact_installed_probe_shell(evidence_dir: Path) -> str:
   architecture="$7"
   metadata_manifest_url="${{8:-$manifest_url}}"
   wait_for_service
-  check_binary_versions "$package_version"
+  check_binary_versions "$package_version" "$artifact"
   dpkg-query -W -f='${{Version}}' capsem | grep -Fx "$package_version"
   {shlex.quote(sys.executable)} build_system/scripts/release/verify-installed-release.py \
     --capsem "$CAPSEM_BIN" \
diff --git a/build_system/tests/release/test_deb_package_portability.py b/build_system/tests/release/test_deb_package_portability.py
index 2fbd37f26..d6fd42a71 100644
--- a/build_system/tests/release/test_deb_package_portability.py
+++ b/build_system/tests/release/test_deb_package_portability.py
@@ -78,3 +78,83 @@ def test_manifest_metadata_requires_one_package_owned_member(package: Path, coun
     _write_synthetic_deb(tree, package)
     with pytest.raises(SystemExit, match=f"exactly one manifest metadata, found {count}"):
         release_installed_probe.packaged_manifest_metadata(package)
+
+
+def test_installed_probe_checks_the_binaries_the_package_ships(package: Path) -> None:
+    """A transition installs an older package whose binary set differs.
+
+    0.6.3 shipped capsem-port-router (and no capsem-router); the probe checked
+    every current binary name against it and failed the release glow-up on a
+    binary that package never had. It checks what the package ships.
+    """
+    tree = package.parent / "tree"
+    for name in ("capsem-service", "capsem-port-router", "capsem-app"):
+        (tree / "usr/bin" / name).write_bytes(b"old package binary")
+    package.unlink()
+    _write_synthetic_deb(tree, package)
+
+    assert release_installed_probe.packaged_host_binaries(package) == ("capsem", "capsem-service")
+
+
+def test_installed_probe_shell_checks_each_artifact_payload(tmp_path: Path) -> None:
+    shell = release_installed_probe.exact_installed_probe_shell(tmp_path)
+    assert 'check_binary_versions "$package_version" "$artifact"' in shell
+    assert "packaged_host_binaries" in shell
+
+
+def _public_transition_version_check(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> str:
+    """The rendered public transition script's binary check, as bash."""
+    import re
+
+    from capsem_builder.release.tools import check_public_binary_release as public
+
+    scripts: list[str] = []
+    monkeypatch.setattr(public.shutil, "which", lambda _name: "/usr/bin/docker")
+    monkeypatch.setattr(
+        public, "linux_amd64_current_package", lambda manifest: {"version": manifest["version"]}
+    )
+    monkeypatch.setattr(public.subprocess, "run", lambda argv, **_: scripts.append(argv[-1]))
+    public.run_docker_binary_transition_smoke(
+        older_manifest={"version": "0.6.3"},
+        newer_manifest={"version": "0.6.4"},
+        install_script_url="http://127.0.0.1:1/install.sh",
+        docker_image="unused",
+        work_dir=tmp_path / "work",
+    )
+    monkeypatch.undo()  # the stubs patched the shared subprocess module
+    match = re.search(r"^check_binary_versions\(\) \{\n.*?^\}\n", scripts[0], re.S | re.M)
+    assert match, scripts[0]
+    return match.group(0)
+
+
+@pytest.mark.parametrize("owned_router", [False, True])
+def test_public_transition_checks_the_binaries_the_installed_package_owns(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, owned_router: bool
+) -> None:
+    """The older public package predates capsem-router; checking the current
+    binary names against it failed a release on a binary it never shipped.
+    A binary the installed package does own must still be present."""
+    import subprocess
+
+    function = _public_transition_version_check(tmp_path, monkeypatch)
+    home = tmp_path / "home"
+    (home / ".capsem/bin").mkdir(parents=True)
+    for name in ("capsem", "capsem-service"):
+        tool = home / ".capsem/bin" / name
+        tool.write_text("#!/bin/sh\necho " + name + " 0.6.3\n")
+        tool.chmod(0o755)
+    owned = ["/usr/bin/capsem", "/usr/bin/capsem-service"] + (["/usr/bin/capsem-router"] if owned_router else [])
+    stubs = tmp_path / "stubs"
+    stubs.mkdir()
+    (stubs / "dpkg").write_text("#!/bin/sh\nprintf '%s\\n' " + " ".join(owned) + "\n")
+    (stubs / "su").write_text('#!/bin/sh\nshift; exec sh -c "$2"\n')
+    for stub in stubs.iterdir():
+        stub.chmod(0o755)
+    result = subprocess.run(
+        ["bash", "-c", "set -euo pipefail\n" + function + "\ncheck_binary_versions 0.6.3\n"],
+        env={"PATH": f"{stubs}:/usr/bin:/bin", "HOME": str(home)},
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    assert (result.returncode == 0) is (not owned_router), result.stderr
diff --git a/build_system/tests/release/test_release_glowup.py b/build_system/tests/release/test_release_glowup.py
index 98c3cd139..891bea140 100644
--- a/build_system/tests/release/test_release_glowup.py
+++ b/build_system/tests/release/test_release_glowup.py
@@ -1659,7 +1659,7 @@ def capture(command: list[str], **_kwargs) -> None:
         assert "build_system/scripts/release/verify-installed-release.py" in script
         assert '"$CAPSEM_BIN" doctor' in script
         assert "build_system/scripts/build/run-installed-winterfell.py" in script
-        assert "capsem-mock-server" in script
+        assert "packaged_host_binaries" in script  # each package holds itself to its own payload
         assert "update --yes" not in script
     assert "update --yes" not in tamper_script
     assert "update --yes" not in incompatible_script