diff --git a/scripts/validation/historiangw-131/README.md b/scripts/validation/historiangw-131/README.md
index d3d84c3f..bad31ee6 100644
--- a/scripts/validation/historiangw-131/README.md
+++ b/scripts/validation/historiangw-131/README.md
@@ -1,3 +1,10 @@
+**Landed:** OtOpcUa master `230cef4e` consumes the published Client/Contracts1.0.0;
+historiangw#131 is closed with verification. The change is merged into this SDK2
+branch. The patch below is a historical/replay input; the validator recognizes
+an already migrated checkout. [Master verification](../../../docs/plans/evidence/2026-11-10-historiangw-131.json)
+records the whole-solution zero-warning build,523 Gateway passes,1,002 Runtime
+passes and package hashes. SDK2 resource/release gates remain separate.
+
 # HistorianGateway consumer TLS migration — issue 131
 
 `consumer-1.0.0.patch` is a reviewable consumer change, kept separate from the
diff --git a/scripts/validation/historiangw-131/validate.py b/scripts/validation/historiangw-131/validate.py
index 73a747e4..134d2125 100644
--- a/scripts/validation/historiangw-131/validate.py
+++ b/scripts/validation/historiangw-131/validate.py
@@ -61,7 +61,16 @@ metadata = {'utc':datetime.datetime.now(datetime.timezone.utc).isoformat(),'cons
 (out/'metadata.json').write_text(json.dumps(metadata,indent=2))
 consumer = out/'consumer'; archive(root,sha,consumer)
 subprocess.run(['git','init','-q',str(consumer)],check=True)
-subprocess.run(['git','-C',str(consumer),'apply',str(patch)],check=True)
+check = subprocess.run(['git','-C',str(consumer),'apply','--check',str(patch)],capture_output=True,text=True)
+if check.returncode == 0:
+    subprocess.run(['git','-C',str(consumer),'apply',str(patch)],check=True)
+    metadata['consumer_patch_state'] = 'applied-to-archive'
+else:
+    reverse = subprocess.run(['git','-C',str(consumer),'apply','--reverse','--check',str(patch)],capture_output=True,text=True)
+    if reverse.returncode:
+        raise RuntimeError('Consumer neither accepts the migration patch nor contains it completely: ' + check.stderr)
+    metadata['consumer_patch_state'] = 'already-present-in-consumer'
+
 if not published:
     hg = out/'historiangw-source'; archive(a.hg_root,hg_sha,hg)
     adapter = consumer/'src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.csproj'