diff --git a/tests/Aetheria.Shared.Tests/RunSaveCompatibilityTests.cs b/tests/Aetheria.Shared.Tests/RunSaveCompatibilityTests.cs
new file mode 100644
index 000000000..8b8c98217
--- /dev/null
+++ b/tests/Aetheria.Shared.Tests/RunSaveCompatibilityTests.cs
@@ -0,0 +1,33 @@
+using System;
+using System.IO;
+using System.Linq;
+using GameCult.Caching;
+using GameCult.Caching.MessagePack;
+using Xunit;
+
+// tests/vectors/cultlib-1.0.60/run.cc is a run.cc written by Aetheria on CultLib 1.0.60 (64 zones, factions, one entity).
+// A player's save outlives the runtime that wrote it, so the current runtime must open it as compatible drift.
+public sealed class RunSaveCompatibilityTests : IDisposable
+{
+    private readonly string _root = Path.Combine(Path.GetTempPath(), "aetheria-runcompat-" + Guid.NewGuid().ToString("N"));
+
+    public RunSaveCompatibilityTests() => Directory.CreateDirectory(_root);
+
+    public void Dispose() => Directory.Delete(_root, true);
+
+    [Fact]
+    public void ARunWrittenByCultLib1060OpensWithEveryZoneAndFactionResolving()
+    {
+        var run = Path.Combine(_root, "run.cc");
+        File.Copy(Path.Combine(RunStartTests.FindRepoRoot(), "tests", "vectors", "cultlib-1.0.60", "run.cc"), run);
+        using var cache = new CultCache(TestCatalog.Registry());
+        cache.AddBackingStore(new SingleFileMessagePackBackingStore(TestCatalog.Repo, true), AetheriaStores.CatalogTypes);
+        cache.AddBackingStore(new SingleFileMessagePackBackingStore(run), AetheriaStores.RunTypes);
+        var saved = cache.GetGlobal<SavedGame>();
+        Assert.NotNull(saved);
+        Assert.NotEmpty(saved.Zones);
+        Assert.NotEmpty(saved.Factions);
+        Assert.All(saved.Zones, zone => Assert.NotNull(cache.Get(zone)));
+        Assert.All(saved.Factions, faction => Assert.NotNull(cache.Get(faction)));
+    }
+}
diff --git a/tests/Aetheria.Shared.Tests/ShipAuthoringTests.cs b/tests/Aetheria.Shared.Tests/ShipAuthoringTests.cs
index cb4d12d5f..850e83dfd 100644
--- a/tests/Aetheria.Shared.Tests/ShipAuthoringTests.cs
+++ b/tests/Aetheria.Shared.Tests/ShipAuthoringTests.cs
@@ -197,6 +197,25 @@ public sealed class ShipAuthoringTests
         Assert.IsType<NotSupportedException>(error.InnerException);
     }
 
+    // A store format this runtime does not know is refused on read with NotSupportedException from the attach; Load names the file.
+    [Fact]
+    public async Task LoadNamesTheFileWhoseStoreFormatIsNewer()
+    {
+        using var directory = new TempDirectory();
+        var path = Path.Combine(directory.Path, "newer.cc");
+        using (var cache = ShipAuthoringStore.Open(path, writable: true))
+        {
+            ShipAuthoringStore.Write(cache, Fixture().Hull, Fixture().Visual);
+            await cache.FlushAsync();
+        }
+        var snapshot = CultDocumentMessagePackSerialization.DeserializeSnapshot(File.ReadAllBytes(path));
+        snapshot.FormatVersion = "cultcache.store.v9";
+        File.WriteAllBytes(path, CultDocumentMessagePackSerialization.SerializeSnapshot(snapshot));
+        var error = Assert.Throws<InvalidOperationException>(() => ShipAuthoringStore.Load(path));
+        Assert.Contains(path, error.Message);
+        Assert.IsType<NotSupportedException>(error.InnerException);
+    }
+
     // Decodes one record's payload of the named schema to its slot array, lets the edit change it, and stores it again.
     private static void RewritePayload(string path, string schemaName, Action<object[]> edit)
     {
diff --git a/tests/vectors/cultlib-1.0.60/run.cc b/tests/vectors/cultlib-1.0.60/run.cc
new file mode 100644
index 000000000..fc2a4e76e
Binary files /dev/null and b/tests/vectors/cultlib-1.0.60/run.cc differ