diff --git a/docs/reverse-engineering/grpc-interface-versions.md b/docs/reverse-engineering/grpc-interface-versions.md
index 5bf1b89..a2f91bb 100644
--- a/docs/reverse-engineering/grpc-interface-versions.md
+++ b/docs/reverse-engineering/grpc-interface-versions.md
@@ -18,8 +18,9 @@
 > captured correctly; the table uses a unified column header for readability.
 
 > **Status note:** `StatusService.GetStatusInterfaceVersion` returned UiVersion=4, UiError=0 on the live
-> 2023 R2 server. Status is classified as reachability-only — its version integer carries no semantic
-> meaning for the SDK's byte serializers — so its UiVersion is not gated and not asserted in tests.
+> 2023 R2 server. This differs from the historical 0 observed on 2020 WCF — both are reachability-only.
+> Status is classified as reachability-only: its version integer carries no semantic meaning for the
+> SDK's byte serializers, so its UiVersion is not gated and not asserted in tests.
 
 ## Evidence Test
 
diff --git a/src/AVEVA.Historian.Client/HistorianServerVersionGate.cs b/src/AVEVA.Historian.Client/HistorianServerVersionGate.cs
index cc69813..8e35bcd 100644
--- a/src/AVEVA.Historian.Client/HistorianServerVersionGate.cs
+++ b/src/AVEVA.Historian.Client/HistorianServerVersionGate.cs
@@ -29,8 +29,9 @@ internal enum HistorianServiceInterface
 ///   <item>Retrieval (<c>Retr</c>) interface version = 4</item>
 ///   <item>Transaction (<c>Trx</c>) interface version = 2</item>
 /// </list>
-/// The Status (<c>Stat</c>) service's <c>GetInterfaceVersion</c> returns 0 (not a real
-/// version), so the Status interface is validated for reachability only, never value.
+/// The Status (<c>Stat</c>) service's <c>GetInterfaceVersion</c> is not a real version (0 on
+/// 2020 WCF, 4 on 2023 R2 gRPC) — it carries no meaning for the byte serializers either way — so
+/// the Status interface is validated for reachability only, never value.
 ///
 /// A 2023 R2 gRPC server reports History interface version 12 even though it carries the
 /// same proven 2020 native buffers. That value is captured and accepted (see
@@ -59,7 +60,8 @@ internal static class HistorianServerVersionGate
 
     /// <summary>
     /// True when the service interface reports a meaningful version that should be matched.
-    /// Status is reachability-only (its <c>GetInterfaceVersion</c> returns 0).
+    /// Status is reachability-only (its <c>GetInterfaceVersion</c> is not a real version —
+    /// 0 on 2020 WCF, 4 on 2023 R2 gRPC).
     /// </summary>
     public static bool IsValueGated(HistorianServiceInterface service) => service switch
     {
diff --git a/tests/AVEVA.Historian.Client.Tests/GrpcInterfaceVersionEvidenceTests.cs b/tests/AVEVA.Historian.Client.Tests/GrpcInterfaceVersionEvidenceTests.cs
index 2d0d854..b90554a 100644
--- a/tests/AVEVA.Historian.Client.Tests/GrpcInterfaceVersionEvidenceTests.cs
+++ b/tests/AVEVA.Historian.Client.Tests/GrpcInterfaceVersionEvidenceTests.cs
@@ -72,7 +72,8 @@ public sealed class GrpcInterfaceVersionEvidenceTests
         Assert.Equal(0u, transaction.Error);
         Assert.Equal(2u, transaction.Version);
 
-        // Status: reachability-only — UiError must be 0; UiVersion is intentionally 0 by design.
+        // Status: reachability-only — assert UiError==0 only; UiVersion is not value-gated
+        // (observed 4 on 2023 R2 gRPC, 0 on 2020 WCF).
         Assert.Equal(0u, status.UiError);
     }