# Project status: Atlas billing migration

**Reporting period** 1–30 September 2026 · **Overall** Amber on schedule, green on scope and budget · **Next gate** Parallel run starts 19 October

The Atlas migration moves Northline Studio's subscription billing off the legacy invoice service onto the ledger platform. All six workstreams are staffed; the ledger service is in active development and the first shadow invoices reconciled to the cent in September. The only open risk is the dunning rebuild, which is two weeks behind after a payment-provider sandbox outage early in the month.

## Delivery schedule

```mermaid
gantt
    title Atlas billing migration — plan and forecast
    dateFormat YYYY-MM-DD
    axisFormat %d %b
    section Discovery
    Billing audit          :done,    d1, 2026-08-03, 12d
    Data mapping           :done,    d2, after d1, 9d
    section Build
    Ledger service         :active,  b1, 2026-08-25, 24d
    Invoice migration      :         b2, after b1, 14d
    Dunning rebuild        :crit,    b3, after b2, 10d
    section Cutover
    Parallel run           :         c1, 2026-10-19, 15d
    Regional cutover       :milestone, m1, after c1, 0d
```

## Effort to date

```mermaid
pie title Effort by workstream
    "Ledger service" : 34
    "Invoice migration" : 22
    "Dunning rebuild" : 16
    "Data mapping" : 14
    "QA and cutover prep" : 14
```

## Milestones

| Milestone                       | Target | Status      | Notes                                     |
| ------------------------------- | ------ | ----------- | ----------------------------------------- |
| Billing audit signed off        | 14 Aug | Complete    | 38 legacy behaviours catalogued           |
| Data mapping agreed             | 27 Aug | Complete    | 96% auto-mapped; 14 manual rules remain   |
| Ledger service feature-complete | 18 Sep | In progress | 82% of stories done; 3 blocked on sandbox |
| Shadow invoices reconcile       | 30 Sep | Complete    | 4,120 invoices, zero variance             |
| Parallel run starts             | 19 Oct | Not started | Depends on dunning rebuild                |
| Regional cutover                | 3 Nov  | Not started | Freeze from 30 Oct                        |

## Workstream progress

**Ledger service**

- [x] Double-entry posting engine and account model
- [x] Idempotent payment webhook handling
- [x] Shadow-mode comparison report
- [ ] Proration rules for mid-cycle plan changes
- [ ] Credit-note and refund flows

**Dunning rebuild**

- [x] State machine and retry schedule
- [ ] Payment-provider sandbox integration (blocked: provider outage, restored 26 Sep)
- [ ] Customer email templates signed off by legal
- [ ] Recovery analytics dashboard

**Cutover readiness**

- [x] Rollback plan reviewed with SRE
- [x] Dual-write feature flag in staging
- [ ] Runbook dry run with support team
- [ ] Go/no-go review scheduled

## Risks and decisions needed

> [!NOTE]
> The dunning rebuild can absorb its two-week slip without moving the cutover date, provided the payment-provider sandbox stays available. If the integration is not green by 9 October we will cut over with the legacy dunning flow and migrate it in a second phase.

- **Provider sandbox instability** — medium likelihood, high impact; weekly availability check added.
- **Invoice migration throughput** — migration of 62 months of history currently projects 31 hours against a 24-hour window; sharding by account cohort under test.
- **Support readiness** — training materials are drafted but not yet reviewed; owner to confirm by 10 October.