Downlink — withdraw data from the queue

Withdraws a downlink frame that is waiting in the queue and has not yet been sent to the device. A class A device receives a downlink only in response to its next uplink, so a frame can wait in the queue for hours and can be withdrawn at any point during that time.

Current ONS version

The command is not in the v0.17 description: it was added to the server in August 2026.

Withdrawal works in two modes:

• One frame — by dataId, the identifier of the queue item on the server. This is not the dataId returned in downlink_data_resp: that one is used for downlink_ack_req. The server returns the queue item identifier only in the response to a whole-queue withdrawal (data_ids): the queuing and history commands do not return it.
• The whole device queue — by devEui with "allScheduled": true: all scheduled frames of the device are withdrawn. Without the allScheduled flag the request is rejected, because the queue may hold frames queued by other clients.

Only frames with status 0 (Scheduled) or 4 (Realtime Scheduled) — those not yet handed to a gateway — can be withdrawn. A withdrawn frame is not deleted: in the history (get_downlink_data_req) it stays with status 6 (Canceled) — see frame status. The queue item is looked up within the last month.

Request and response: cancel_downlink_req → cancel_downlink_resp.
Access: a token of any access level; the command withdraws only frames of devices that belong to the application you are connected to.

Request

Fields not marked as required may be omitted.

Field	Type	Description
cmd	string	cancel_downlink_req
operation_id	string	Any string; the server returns it in the response to match the request and the response
dataId	uint64	dataId or devEui is required. Queue item identifier — to withdraw one frame
devEui	string	dataId or devEui is required. Device DevEUI — to withdraw its whole queue; requires allScheduled
allScheduled	bool	Together with devEui. true — withdraw all scheduled frames of the device. Default false

{
    "cmd": "cancel_downlink_req",
    "operation_id": "abc",
    "devEui": "6F1E570FFE14DBFC",
    "allScheduled": true
}

Response

Field	Type	Description
cmd	string	cancel_downlink_resp
operation_id	string	Value from the request
status	uint8	1 — the frame is withdrawn, 2 — not withdrawn
cancelStatus	string	Withdrawal result, see the table below
reason	string	Reason as text
data_id	uint64	Queue item — for a one-frame withdrawal
dev_eui	string	The device
dev_addr, fport, data, mtype	string, uint8, string, uint8	Parameters of the withdrawn frame — only for a one-frame withdrawal with cancelStatus = canceled
count	uint32	Number of withdrawn frames
data_ids	array	Withdrawn queue items — for a whole-queue withdrawal

Fields without a value are omitted from the response.

cancelStatus	status	Meaning
canceled	1	The frame is withdrawn; for the whole queue — all scheduled frames (count, data_ids)
already_canceled	2	The frame was already withdrawn; repeating the request is safe
too_late	2	The frame has already been handed to a gateway or has a final status, or the server picked it up for transmission at the moment of the request
not_found	2	There is no such queue item, or it belongs to another application
not_downlink	2	The item with this identifier is not a downlink
error	2	Neither dataId nor devEui given; whole-queue withdrawal without "allScheduled": true; internal server error

Response examples

The whole device queue is withdrawn:

{
    "cmd": "cancel_downlink_resp",
    "operation_id": "abc",
    "status": 1,
    "cancelStatus": "canceled",
    "reason": "Cancelled every scheduled downlink of the device",
    "dev_eui": "6F1E570FFE14DBFC",
    "count": 2,
    "data_ids": [ 48211, 48212 ]
}

The frame has already been handed to a gateway (status 1, Sent):

{
    "cmd": "cancel_downlink_resp",
    "operation_id": "xyz",
    "status": 2,
    "cancelStatus": "too_late",
    "reason": "Already Sent",
    "data_id": 48213,
    "dev_eui": "6F1E570FFE14DBFC"
}

See also

• Sending data to a device — the whole scenario and frame statuses.
• downlink_purge_req — cancel waiting frames with a high access level token.