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

# Midaz v4 API and deployment model

> Midaz v4 documents the current Ledger API, the CRM and Fees integration model, and the separate Tracer runtime boundary.

<Badge stroke icon="calendar-days" iconType="regular">September 3, 2026</Badge> <Badge stroke icon="file-code" iconType="regular">Product update</Badge> <Badge color="purple" size="lg" stroke icon="eye" iconType="regular">Action required</Badge>

## Affects

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Teams integrating with Midaz CRM or Fees APIs, deploying Midaz with Helm, or using Tracer with Midaz v4.

## What changed

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The Midaz v4 reference now identifies Ledger `/v2` as the current API surface for Core, CRM, and Fees. Ledger `/v1` remains available only for compatibility. The standalone Fees Engine reference was retired; its legacy URLs redirected to their Midaz destinations until September 10, 2026 (see [Page URLs now mirror the navigation](/en/news/2026/september/page-urls-mirror-navigation)).

CRM and Fees run as modules of the unified Midaz Ledger runtime; they are not standalone deployments. CRM account associations use Instruments, and the Fees error reference uses the canonical numeric codes.

Tracer is source available under ELv2 in the Midaz v4 repository, but remains a separately deployed service. Its public HTTP API is `/v1`. Ledger `/v2` can opt in to the reservation integration; Ledger `/v1` does not use it.

## Impact

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**Classification: Action required.**

## What you need to do

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<Steps>
  <Step>Move active CRM and Fees integrations to the Ledger `/v2` reference, and treat `/v1` as a compatibility surface.</Step>
  <Step>Update Helm values and runbooks so CRM and Fees are deployed with Midaz, not as standalone services. Validate any Tracer reservation integration against the v4 deployment guidance.</Step>
</Steps>

### Deadline

Complete this before the next Midaz v4 integration or deployment.