> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zivio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# v3 is now legacy

> v3 remains available for existing integrations; new work should use v4

<Warning>
  **You are reading the v3 documentation.** v3 remains available and supported for existing
  integrations, but it is no longer the current version. New integrations should build on
  [v4](/v4/overview).
</Warning>

### What this means

* **Existing v3 integrations keep working.** Nothing you have built stops functioning, and
  these pages stay published. Every v3 URL is unchanged.
* **New integrations should use v4.** It adds OAuth 2.0 with fine-grained scopes, a much
  richer filtering syntax, considerably wider endpoint coverage, and an MCP server for AI
  assistants.
* **Switch versions** using the version dropdown in the top navigation.

### Moving to v4

[Migrating from v3](/v4/migrating-from-v3) covers the differences in full. In short:

|                | v3                                      | v4                                                  |
| -------------- | --------------------------------------- | --------------------------------------------------- |
| Authentication | `X-API-Key` + `zivio-tenant-id` headers | OAuth 2.0 bearer token                              |
| Permissions    | All-or-nothing                          | Per-request scopes                                  |
| Projects       | `/jobs`                                 | `/projects`                                         |
| Filtering      | Fixed query parameters                  | `filter[]` with operators, OR groups, custom fields |
| AI access      | —                                       | MCP server                                          |

<Note>
  A few v3 resources have no v4 equivalent yet — sales invoices and milestones, skills and
  skill categories, org sub-resources, and supplier catalogs, resources and documents. If
  you depend on those, stay on v3 for now and contact
  [support@zivio.com](mailto:support@zivio.com).
</Note>