diff --git a/examples/ticket_service/ticket_service.py b/examples/ticket_service/ticket_service.py
index 6dfc5f5..0489b31 100644
--- a/examples/ticket_service/ticket_service.py
+++ b/examples/ticket_service/ticket_service.py
@@ -9,6 +9,9 @@ proves the canonical lifecycle:
   C closed     ticket=ID@DOMAIN (closed)    -> archived, ticket not mutated, one notice
   D unknown    ticket=NOPE@DOMAIN           -> quarantined, no reply (no backscatter)
 
+Ticket ids match case-insensitively (`ticket=gs-id@` finds `GS-ID`), because
+forwarders and mailing lists lower-case local-parts in practice.
+
 Resource addresses are correlation identifiers, not credentials: knowing
 one lets you send mail to the ticket, nothing more. Admin endpoints here are
 unauthenticated and meant for local experiments only.
@@ -106,12 +109,14 @@ class TicketService:
                      "requested_interaction": honored}
 
     def _to_resource(self, event, mas, msg):
-        tid = mas["resource_id"]
-        row = self.db.execute("SELECT * FROM tickets WHERE id=? AND domain=?",
-                              (tid, mas["domain"])).fetchone()
+        # Ids match case-insensitively: forwarders and list servers lower-case
+        # local-parts (SCP-7). From here on use the id as issued.
+        row = self.db.execute("SELECT * FROM tickets WHERE id=? COLLATE NOCASE AND domain=?",
+                              (mas["resource_id"], mas["domain"])).fetchone()
         if row is None:
             self._store(None, "quarantined-unknown", event, mas, msg)
             return 202, {"status": "unknown-resource", "action": "quarantined, no reply"}
+        tid = row["id"]
         if row["status"] == "closed":
             self._store(tid, "archived-after-close", event, mas, msg)
             notified = False
@@ -169,13 +174,15 @@ class TicketService:
 
     def close(self, tid: str) -> bool:
         with self.lock, self.db:
-            return self.db.execute("UPDATE tickets SET status='closed' WHERE id=?", (tid,)).rowcount == 1
+            return self.db.execute("UPDATE tickets SET status='closed' WHERE id=? COLLATE NOCASE",
+                                   (tid,)).rowcount == 1
 
     def ticket(self, tid: str) -> Optional[dict]:
-        row = self.db.execute("SELECT * FROM tickets WHERE id=?", (tid,)).fetchone()
+        row = self.db.execute("SELECT * FROM tickets WHERE id=? COLLATE NOCASE", (tid,)).fetchone()
         if row is None:
             return None
-        msgs = self.db.execute("SELECT * FROM messages WHERE ticket_id=? ORDER BY seq", (tid,)).fetchall()
+        msgs = self.db.execute("SELECT * FROM messages WHERE ticket_id=? ORDER BY seq",
+                               (row["id"],)).fetchall()
         return {**dict(row), "messages": [dict(m) for m in msgs]}
 
     def outbox(self) -> list[dict]:
diff --git a/tests/test_end_to_end.py b/tests/test_end_to_end.py
index 9e05a49..cd8ade8 100644
--- a/tests/test_end_to_end.py
+++ b/tests/test_end_to_end.py
@@ -83,6 +83,19 @@ def test_canonical_lifecycle(env):
     assert len(svc.outbox()) == before and len(svc.quarantine()) == 1
 
 
+def test_lower_cased_id_correlates(env):
+    # IONOS forwards and Google Groups members arrive lower-cased (MAS-WP-0003 T04)
+    svc, send, *_ = env
+    send(f"ticket!callback@{D}", "request")
+    d = send(f"ticket=gs-41872+comments@{D}", "via a mailing list")
+    assert d.response == {"status": "correlated", "ticket_id": "GS-41872", "facet": "comments"}
+    assert len(svc.ticket("gs-41872")["messages"]) == 2
+    assert svc.close("gs-41872")
+    d = send(f"ticket=gs-41872@{D}", "after close")
+    assert d.response["ticket_id"] == "GS-41872" and d.response["notified"] is True
+    assert svc.outbox()[-1]["mail_from"] == f"ticket=GS-41872@{D}"   # replies use the issued id
+
+
 def test_send_cap_keeps_replies_in_outbox(env):
     svc, send, *_ = env
     sent = []
diff --git a/workplans/MAS-WP-0005-spec-errata-v0-1-1.md b/workplans/MAS-WP-0005-spec-errata-v0-1-1.md
index d25f8ec..b345e7f 100644
--- a/workplans/MAS-WP-0005-spec-errata-v0-1-1.md
+++ b/workplans/MAS-WP-0005-spec-errata-v0-1-1.md
@@ -52,7 +52,7 @@ fixtures and update the parser, policy and schema.
 
 ```task
 id: MAS-WP-0005-T03
-status: todo
+status: progress
 priority: high
 state_hub_task_id: "7c19e951-7ab4-580c-9e4c-9fead9ee946e"
 ```
@@ -62,6 +62,14 @@ and a list post was lost to its ticket. Make the reference ticket service
 issue and match ids case-insensitively. Crockford base32 is case-insensitive
 by design. Verify on the live MX by repeating the Google Groups post.
 
+- 2026-10-18: implemented. Ticket lookup uses `COLLATE NOCASE` (also in the
+  `ticket()`/`close()` admin calls). Once found, the service stores,
+  replies and reports under the id as issued, so replies keep coming From
+  `ticket=GS-…@`. Test `test_lower_cased_id_correlates` passes, as do all
+  137 tests. Deployed as `mas-live:wp0005-20261018`. A dry check on a copy
+  of the live DB resolves `gs-85qj8wc09p` to `GS-85QJ8WC09P`. Pending:
+  live Google Groups post.
+
 ## v0.2 drafts: SCP-6 and the SCP-7 statute field
 
 ```task