diff --git a/api/client-server/v1/room_send.yaml b/api/client-server/v1/room_send.yaml
index 9c9273df..3ab1ac40 100644
--- a/api/client-server/v1/room_send.yaml
+++ b/api/client-server/v1/room_send.yaml
@@ -76,50 +76,3 @@ paths:
                 type: string
                 description: |-
                   A unique identifier for the event.
-  "/rooms/{roomId}/send/{eventType}":
-    post:
-      summary: Send a message event to the given room.
-      description: |-
-        This endpoint can be used to send a message event to a room; however
-        the lack of a transaction ID means that it is possible to cause message
-        duplication if events are resent on error, so it is preferable to use
-        `PUT /_matrix/client/api/v1/rooms/{roomId}/send/{eventType}/{txnId}`_.
-      security:
-        - accessToken: []
-      parameters:
-        - in: path
-          type: string
-          name: roomId
-          description: The room to send the event to.
-          required: true
-          x-example: "!636q39766251:example.com"
-        - in: path
-          type: string
-          name: eventType
-          description: The type of event to send.
-          required: true
-          x-example: "m.room.message"
-        - in: body
-          name: body
-          schema:
-            type: object
-            example: |-
-              {
-                "msgtype": "m.text",
-                "body": "hello"
-              }
-      responses:
-        200:
-          description: "An ID for the sent event."
-          examples:
-            application/json: |-
-              {
-                  "event_id": "YUwRidLecu"
-              }
-          schema:
-            type: object
-            properties:
-              event_id:
-                type: string
-                description: |-
-                  A unique identifier for the event.
diff --git a/specification/modules/instant_messaging.rst b/specification/modules/instant_messaging.rst
index a58c762f..cd385001 100644
--- a/specification/modules/instant_messaging.rst
+++ b/specification/modules/instant_messaging.rst
@@ -62,10 +62,8 @@ resulting ``mxc://`` URI can then be used in the ``url`` key.
 Recommendations when sending messages
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Clients can send messages using ``POST`` or ``PUT`` requests. Clients SHOULD use
-``PUT`` requests with `transaction IDs`_ to make requests idempotent. This
-ensures that messages are sent exactly once even under poor network conditions.
-Clients SHOULD retry requests using an exponential-backoff algorithm for a
+In the event of send failure, clients SHOULD retry requests using an
+exponential-backoff algorithm for a
 certain amount of time T. It is recommended that T is no longer than 5 minutes.
 After this time, the client should stop retrying and mark the message as "unsent".
 Users should be able to manually resend unsent messages.
@@ -78,8 +76,6 @@ reduce the impact of head-of-line blocking, clients should use a queue per room
 rather than a global queue, as ordering is only relevant within a single room
 rather than between rooms.
 
-.. _`transaction IDs`: `sect:txn_ids`_
-
 Local echo
 ~~~~~~~~~~