diff --git a/content/client-server-api/_index.md b/content/client-server-api/_index.md
index c62938df..7cff2807 100644
--- a/content/client-server-api/_index.md
+++ b/content/client-server-api/_index.md
@@ -2621,6 +2621,8 @@ An example of the capability API's response for this capability is:
 
 ### `m.forget_forced_upon_leave` capability
 
+{{% added-in v="1.18" %}}
+
 This capability has a single flag, `enabled`, which indicates whether or
 not the server automatically forgets rooms which the user has left.
 
diff --git a/data/api/client-server/capabilities.yaml b/data/api/client-server/capabilities.yaml
index df86c2da..f73e8b46 100644
--- a/data/api/client-server/capabilities.yaml
+++ b/data/api/client-server/capabilities.yaml
@@ -51,6 +51,7 @@ paths:
                         $ref: '#/components/schemas/booleanCapability'
                         description: Capability to indicate if the user can change their password.
                       m.forget_forced_upon_leave:
+                        x-addedInMatrixVersion: "1.18"
                         $ref: '#/components/schemas/booleanCapability'
                         description: |-
                           Capability to indicate if the server automatically forgets rooms once the user
diff --git a/data/api/client-server/leaving.yaml b/data/api/client-server/leaving.yaml
index db61818f..424079d5 100644
--- a/data/api/client-server/leaving.yaml
+++ b/data/api/client-server/leaving.yaml
@@ -28,16 +28,15 @@ paths:
 
         If the user was invited to the room, but had not joined, this call
         serves to reject the invite.
-
-        Servers MAY additionally forget the room when this endpoint is called –
-        just as if the user had also invoked [`/forget`](/client-server-api/#post_matrixclientv3roomsroomidforget).
-        Servers that do this, MUST inform clients about this behavior using the
-        [`m.forget_forced_upon_leave`](/client-server-api/#mforget_forced_upon_leave-capability)
-        capability.
-
-        If the server doesn't automatically forget the room, the user will still be
-        allowed to retrieve history from the room which they were previously allowed
-        to see.
+      x-changedInMatrixVersion:
+        "1.18": |
+          Servers MAY additionally forget the room when this endpoint is called –
+          just as if the user had also invoked [`/forget`](/client-server-api/#post_matrixclientv3roomsroomidforget).
+          Servers that do this, MUST inform clients about this behavior using the
+          [`m.forget_forced_upon_leave`](/client-server-api/#mforget_forced_upon_leave-capability)
+          capability. If the server doesn't automatically forget the room, the user
+          will still be allowed to retrieve history from the room which they were
+          previously allowed to see.
       operationId: leaveRoom
       security:
         - accessTokenQuery: []