# API changes: September 27, 2026

[← Changelog](/docs/changelog) · [September 2026](/docs/changelog/2026-09)

### FIX-0927-3: business process operations on an account without the module answer 409 instead of 404

**Before**

On an account where Business Processes are not included in the plan or are switched off in settings, only the list of running workflows answered `409 BIZPROC_MODULE_NOT_ENABLED` — [GET /v1/workflows](/docs/automation/workflows/list). The other four operations of the section answered `404 ENTITY_NOT_FOUND` in the same account state: [POST /v1/workflows/start](/docs/automation/workflows/start), [DELETE /v1/workflows/:id](/docs/automation/workflows/terminate), [POST /v1/workflows/activity-log](/docs/automation/workflows/activity-log) and [POST /v1/workflows/event](/docs/automation/workflows/event). That answer looked like a wrong template, document or workflow ID, although the IDs were correct.

**After**

All five operations of the section answer the same way in this account state: `409 BIZPROC_MODULE_NOT_ENABLED`. The message names the Bitrix24 method that was called, both possible causes and the action to take: ask an account administrator to enable Business Processes. Other errors of these operations are unchanged.

**Impact on integrators**

No action is required: the refusal was a 4xx and stays a 4xx, and the former `404 ENTITY_NOT_FOUND` was never documented for this state. Retrying with other IDs does not help while Business Processes are unavailable on the account. For stopping a workflow, `404 ENTITY_NOT_FOUND` still means the workflow instance was not found, while `409 BIZPROC_MODULE_NOT_ENABLED` means the module is unavailable and the workflow was not stopped. An integration that treated 404 as a sign of an already finished workflow now sees 409 on such an account, and the workflow is not stopped.

### NEW-0927-5: Checklist actions and attaching a file to a task

Ten named `/v1/tasks/:taskId/checklist/...` and `/v1/tasks/:taskId/files/attach` routes are now available for saving a tree, managing members, moving and completing checklist items, managing checklist attachments, and attaching a Disk file to a task. Each route returns the Bitrix24 method result in `data`.