From 533d5e0a7abe3d13ed2490194b0b0d52ec8aedaf Mon Sep 17 00:00:00 2001
From: Andrew Morgan <andrew@amorgan.xyz>
Date: Tue, 30 Sep 2025 17:10:32 +0100
Subject: [PATCH] Remove unstable prefixes for MSC2732

This MSC was accepted in 2022. We shouldn't need to continue supporting the unstable field names.
---
 synapse/handlers/e2e_keys.py    |  4 +---
 synapse/rest/client/sync.py     |  3 ---
 tests/handlers/test_e2e_keys.py | 23 -----------------------
 3 files changed, 1 insertion(+), 29 deletions(-)

diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index b9abad218..a257f72a5 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -873,9 +873,7 @@ class E2eKeysHandler:
             log_kv(
                 {"message": "Did not update one_time_keys", "reason": "no keys given"}
             )
-        fallback_keys = keys.get("fallback_keys") or keys.get(
-            "org.matrix.msc2732.fallback_keys"
-        )
+        fallback_keys = keys.get("fallback_keys")
         if fallback_keys and isinstance(fallback_keys, dict):
             log_kv(
                 {
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index 5e0596d1b..c7117e660 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -363,9 +363,6 @@ class SyncRestServlet(RestServlet):
 
         # https://github.com/matrix-org/matrix-doc/blob/54255851f642f84a4f1aaf7bc063eebe3d76752b/proposals/2732-olm-fallback-keys.md
         # states that this field should always be included, as long as the server supports the feature.
-        response["org.matrix.msc2732.device_unused_fallback_key_types"] = (
-            sync_result.device_unused_fallback_key_types
-        )
         response["device_unused_fallback_key_types"] = (
             sync_result.device_unused_fallback_key_types
         )
diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
index fda485d41..5fcbcc41e 100644
--- a/tests/handlers/test_e2e_keys.py
+++ b/tests/handlers/test_e2e_keys.py
@@ -410,7 +410,6 @@ class E2eKeysHandlerTestCase(unittest.HomeserverTestCase):
         device_id = "xyz"
         fallback_key = {"alg1:k1": "fallback_key1"}
         fallback_key2 = {"alg1:k2": "fallback_key2"}
-        fallback_key3 = {"alg1:k2": "fallback_key3"}
         otk = {"alg1:k2": "key2"}
 
         # we shouldn't have any unused fallback keys yet
@@ -531,28 +530,6 @@ class E2eKeysHandlerTestCase(unittest.HomeserverTestCase):
             {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key2}}},
         )
 
-        # using the unstable prefix should also set the fallback key
-        self.get_success(
-            self.handler.upload_keys_for_user(
-                local_user,
-                device_id,
-                {"org.matrix.msc2732.fallback_keys": fallback_key3},
-            )
-        )
-
-        claim_res = self.get_success(
-            self.handler.claim_one_time_keys(
-                {local_user: {device_id: {"alg1": 1}}},
-                self.requester,
-                timeout=None,
-                always_include_fallback_keys=False,
-            )
-        )
-        self.assertEqual(
-            claim_res,
-            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key3}}},
-        )
-
     def test_fallback_key_bulk(self) -> None:
         """Like test_fallback_key, but claims multiple keys in one handler call."""
         alice = f"@alice:{self.hs.hostname}"