1 files changed, 12 insertions, 1 deletions
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 488604a30c..6a8c7cb1c9 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -2,7 +2,7 @@
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #
 # Copyright 2014-2021 The Matrix.org Foundation C.I.C.
-# Copyright (C) 2023 New Vector, Ltd
+# Copyright (C) 2023-2024 New Vector, Ltd
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -780,6 +780,17 @@ class ServerConfig(Config):
         else:
             self.delete_stale_devices_after = None
 
+        # The maximum allowed delay duration for delayed events (MSC4140).
+        max_event_delay_duration = config.get("max_event_delay_duration")
+        if max_event_delay_duration is not None:
+            self.max_event_delay_ms: Optional[int] = self.parse_duration(
+                max_event_delay_duration
+            )
+            if self.max_event_delay_ms <= 0:
+                raise ConfigError("max_event_delay_duration must be a positive value")
+        else:
+            self.max_event_delay_ms = None
+
     def has_tls_listener(self) -> bool:
         return any(listener.is_tls() for listener in self.listeners)