n8n Upgrade: Detect Affected Workflows with Broken Connections

Summary

This workflow helps n8n administrators identify workflows that may have been affected by a past upgrade (specifically n8n version 0.214.3) where multi-output nodes (like If, Switch, Compare Datasets) could have their output connections accidentally re-wired. It provides a self-service webhook endpoint that returns an HTML report listing all workflows with potentially broken connections, making it easy to audit and fix them.

Node-by-Node Walkthrough

• Webhook (No auth) — Listens for HTTP GET requests at the path /webhooks/affected-workflows. When a user visits this URL in their browser, the workflow is triggered. The response mode is set to "Response Node", meaning the final output will be sent back directly.
• Get all workflows (API Key auth) — Uses the n8n API to fetch all workflows from the instance. You must configure this node with an n8n API credential (a personal access token created under Settings > n8n API). The node has no filters, so it retrieves every workflow.
• Parse potentially affected workflows (Code node, no auth) — A JavaScript code node that loops through each workflow, inspects its connections, and checks if any multi-output node (defined in the MULTI_OUTPUT_NODES array) has empty outputs. If a node has fewer connected outputs than expected, it is flagged as potentially affected. The node outputs a JSON object with an array of affected workflows, each containing workflowId, workflowName, active, and potentiallyAffectedNodes.
• Generate Report (HTML node, no auth) — Creates a static HTML document with a styled container, a heading, and an empty list. This serves as the shell for the interactive report generated by the next node.
• Serve HTML Report (Respond to Webhook node, no auth) — Takes the HTML template from the previous node and injects JavaScript that parses the affected workflows data (from the code node) and dynamically builds a list of clickable links. Each link opens the workflow in a new tab so the admin can inspect and fix the connections. The response headers are set to text/html; charset=utf-8.

Setup Instructions

1. Prerequisites: You must have admin access to the n8n instance (the workflow must be run by the instance owner).
2. Create an n8n API key: Go to Settings > n8n API in your n8n instance and generate a personal access token. Copy the token.
3. Configure the "Get all workflows" node: Add an n8n credential of type "API Key" and paste the token. Leave the filters empty.
4. Customize multi-output nodes (if needed): The code node contains a list MULTI_OUTPUT_NODES with the default nodes (compareDatasets, switch, if). If you have community nodes with multiple outputs, add them to this array with their correct output count.
5. Activate the workflow: Toggle the workflow to active.
6. Use the report: Open your browser and navigate to {YOUR_INSTANCE_URL}/webhooks/affected-workflows. The page will list all affected workflows. Click on a row to open the workflow in a new tab — inspect the connections and re-wire them if needed.

Use Cases & Variations

• Post-upgrade audit: Run this workflow after every n8n upgrade to catch connection issues early.
• Customized detection: Extend the MULTI_OUTPUT_NODES array in the code node to include any custom node type that has multiple outputs.
• Slack/Email notification: Instead of serving an HTML report, you could send the list of affected workflows to a Slack channel or email using additional nodes.
• Scheduled scanning: Replace the Webhook trigger with a Schedule trigger to run the check daily and automatically notify the admin.

{
  "meta": {
    "instanceId": "workflow-70ba7a9d",
    "versionId": "1.0.0",
    "createdAt": "2025-09-29T07:07:42.351971",
    "updatedAt": "2025-09-29T07:07:42.351990",
    "owner": "n8n-user",
    "license": "MIT",
    "category": "automation",
    "status": "active",
    "priority": "high",
    "environment": "production"
  },
  "nodes": [
    {
      "id": "b83bfb2d-6d1b-4984-8fc4-6cf0a35309dc",
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      "type": "n8n-nodes-base.stickyNote",
      "position": [
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      "parameters": {
        "width": 1074,
        "height": 468,
        "content": "# ⚠️ When and how to use this workflow\n\nIf you previously upgraded to n8n version `0.214.3`, some of your workflows might have accidentally been re-wired in the wrong way. This affected nodes which have more than 1 output, such as `If`, `Switch`, and `Compare Datasets`.\n\nThis workflow helps you identify potentially affected workflows and nodes that you should  check.\n\n**❗️Please ensure to run this workflow as the instance owner❗️**\n\n1. Configure the \"Get all workflows\" node to use your n8n API key. (You can find/create your API key under \"Settings > n8n API\")\n2. If you have community nodes installed that have more than 1 output, add them to the constant `MULTI_OUTPUT_NODES` in the \"Parse potentially affected workflows\" code node.\n3. Activate the workflow\n4. Visit `{YOUR_INSTANCE_URL}/webhooks/affected-workflows` from your browser\n5. The report will list potentially affected workflows/nodes.\n    1. The square brackets after the workflow name list the potentially affected nodes\n    2. Inspect each reported workflow individually (you can click on a row to open it in a new tab)\n    3. **Verify that the correct outbound connectors are used to connect subsequent nodes.**"
      },
      "typeVersion": 1,
      "notes": "This stickyNote node performs automated tasks as part of the workflow."
    },
    {
      "id": "ba065db3-be3c-4694-afbd-c9095526adf6",
      "name": "Get all workflows",
      "type": "n8n-nodes-base.n8n",
      "position": [
        1540,
        1460
      ],
      "parameters": {
        "filters": {}
      },
      "credentials": {
        "n8nApi": {
          "id": "{{ $credentials.n8nApi.id }}",
          "name": "n8n account"
        }
      },
      "typeVersion": 1,
      "notes": "This n8n node performs automated tasks as part of the workflow."
    },
// ... truncated (copy to see full JSON)