From 09e745bcdfad5b942f4be4af495f9287a319cb18 Mon Sep 17 00:00:00 2001
From: timedout <me@nexy7574.co.uk>
Date: Tue, 21 Apr 2026 21:53:17 +0100
Subject: [PATCH] Specify `replaces_state` in `ClientEvent` (#2345)

Signed-off-by: timedout <git@nexy7574.co.uk>
---
 .../client_server/newsfragments/2345.feature       |  1 +
 .../definitions/client_event_without_room_id.yaml  | 14 +++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)
 create mode 100644 changelogs/client_server/newsfragments/2345.feature

diff --git a/changelogs/client_server/newsfragments/2345.feature b/changelogs/client_server/newsfragments/2345.feature
new file mode 100644
index 00000000..b4fd7c2a
--- /dev/null
+++ b/changelogs/client_server/newsfragments/2345.feature
@@ -0,0 +1 @@
+Specify `unsigned.replaces_state` in client-formatted events. Contributed by @nexy7574.
diff --git a/data/api/client-server/definitions/client_event_without_room_id.yaml b/data/api/client-server/definitions/client_event_without_room_id.yaml
index fcdf32ea..b8011ab1 100644
--- a/data/api/client-server/definitions/client_event_without_room_id.yaml
+++ b/data/api/client-server/definitions/client_event_without_room_id.yaml
@@ -105,9 +105,10 @@ properties:
         type: string
       prev_content:
         description: |
-          The previous `content` for this event. This field is generated
-          by the local homeserver, and is only returned if the event is a state event,
-          and the client has permission to see the previous content.
+          The `content` of the previous state event that was replaced by this event.
+          This field is generated by the local homeserver, and is only returned if
+          the event is a state event, and the client has permission to see the
+          previous event.
         x-changedInMatrixVersion:
           "1.2": |
             Previously, this field was specified at the top level of returned
@@ -117,6 +118,13 @@ properties:
             this.
         title: EventContent
         type: object
+      replaces_state:
+        description: |
+          The event ID of the state event replaced by this event. This field is generated
+          by the local homeserver, and is only returned if the event is a state event.
+          Unlike `prev_content`, this field is included regardless of history visibility.
+        type: string
+        x-addedInMatrixVersion: "1.19"
       membership:
         description: |
           The room membership of the user making the request, at the time of the event.