diff --git a/scripts/validation/scadabridge-sdk-compatibility/README.md b/scripts/validation/scadabridge-sdk-compatibility/README.md
index 62a012776..5206ff21d 100644
--- a/scripts/validation/scadabridge-sdk-compatibility/README.md
+++ b/scripts/validation/scadabridge-sdk-compatibility/README.md
@@ -45,7 +45,11 @@ roundtrips, durable hierarchical browse including the native alarm, data quality
 and timestamps on raw and UNS subscriptions, alarm filter/ConditionRefresh,
 disconnect/reconnect, and (ScadaBridge#125) a Server-object alarm subscription on
 the reconnected session whose ConditionRefresh must replay the active native
-condition (11 cases per trusted leg). History
+condition (11 cases per trusted leg). The API key has the production
+`ApiKeySecret.Generate` shape and length, 65 characters (lmxopcua#880): the
+55-character `otua_matrix_` key used before stayed under SDK 2's 64-byte
+`RsaEncryptedSecret` threshold, so it could not show whether an SDK 2 consumer
+still sends the password in a format an SDK 1.5 server decrypts. History
 and Part 9 acknowledgment are not exposed by the inspected consumer interfaces;
 the parent Shared/CLI matrix covers those application services instead.
 
@@ -97,3 +101,16 @@ legs (11/11 cases each). Loss-to-backup timings are the same on both versions:
 waits out a connect timeout against the silent primary. `rig-failover.sh` passed
 9/9 against the docker-dev pair (image SDK 2.0.1), central-1 killed, about 20 s
 to central-2.
+
+Run 2026-11-12 (ScadaBridge#125) with the consumer itself on SDK **2.0.1**
+(ScadaBridge `731d1ed7`, on main as `a2e9d718`; the DCL sends UserName passwords in the
+legacy RSA format), 65-character key, against the SDK 1.5.378 baseline
+(`83ed880e`) and master `412da27c` (SDK 2.0.1): matrix 11/11 in None, Sign and
+SignAndEncrypt on both with the ACL off and on, all 8 trust controls failed
+closed (0x80130000 / 0x801A0000), failover 8/8 legs. `kill` reaches the backup
+in about 20 s as before; `freeze` is now detected in about 15 s (SDK 2
+keep-alive; about 20 s on the SDK 1.5 client) and reaches the backup in 81–125 s.
+A mutation run with the consumer's UserName identity reverted to the SDK 2
+default handler fails every trusted leg against the baseline with
+`BadIdentityTokenInvalid` (0x80200000) and passes against master, which is
+lmxopcua#880 reproduced from the consumer side.
diff --git a/scripts/validation/scadabridge-sdk-compatibility/run.py b/scripts/validation/scadabridge-sdk-compatibility/run.py
index 1de2e7e45..535ae8961 100644
--- a/scripts/validation/scadabridge-sdk-compatibility/run.py
+++ b/scripts/validation/scadabridge-sdk-compatibility/run.py
@@ -16,7 +16,11 @@ SECURITY = {"None": "none", "Sign": "sign", "SignAndEncrypt": None}
 
 def leg_env(mode):
     env = os.environ.copy()
-    env["OPCUA_MATRIX_PASSWORD"] = "otua_matrix_" + secrets.token_urlsafe(32)
+    # The production ApiKeySecret.Generate shape and length, 65 characters (lmxopcua#880, ScadaBridge#125): the
+    # 55-character key used before stayed under SDK 2's 64-byte RsaEncryptedSecret threshold, so it could not show
+    # whether an SDK 2 consumer still sends the password in a format an SDK 1.5 server decrypts.
+    env["OPCUA_MATRIX_PASSWORD"] = "otua_" + secrets.token_hex(8) + "_" + secrets.token_urlsafe(32)
+    assert len(env["OPCUA_MATRIX_PASSWORD"]) == 65
     for name in ("SCADABRIDGE_PROBE_PKI", "SCADABRIDGE_PROBE_SERVER_CERTS", "OPCUA_MATRIX_SERVER_SECURITY"):
         env.pop(name, None)
     if SECURITY[mode]: