---
title: "Keep old prices as archived catalogue · Agent Wranglers"
url: https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers/grandfathered-prices
id: PRC-16
level: Recommended
applies: payments
updated: 2026-10-27
build: a2a6bdfed830
tokens: 1020
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Keep old prices as archived catalogue prices with an end date

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Plan changes, trials and free tiers](https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-27.

- ID: PRC-16
- Level: Recommended
- Chapter: [Plan changes, trials and free tiers](https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers.md)
- Rule: When a plan or price changes, keep existing subscribers on the archived price with a written end date, or no end date by decision. Move them in batches by a job that checks each notice first.
- Check: A test archives a price with 3 subscribers. A new checkout with that price is refused. The migration job moves only subscribers whose sent notice fits its window, at their renewal date. Each keeps every entitlement the old plan gave.
- Applies when: The project takes payments.
- How: Grandfathering is a promise, so record it. Archive the old price in the [versioned catalogue](https://agentwranglers.se/playbook/pricing/plans-and-prices/price-catalogue.md) so no new customer can choose it. Store on each price whether it is grandfathered and until when. Map each old plan to the new one, including its entitlements, so nobody loses a feature by accident. A move that raises the price needs the notice from [Tell subscribers before a price rise](https://agentwranglers.se/playbook/pricing/plans-and-prices/price-increase-notice.md). Move subscribers at their renewal date, never mid-period. List every archived price with its subscriber count each quarter, and retire one only when the count reaches zero.

## Examples

**Using these examples:** they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

### TypeScript example

```ts
export async function migrateGrandfathered(db, oldPriceId: string, newPriceId: string, now = new Date()) {
  const due = await db.subscriptions({ priceId: oldPriceId, renewsBefore: now })
  for (const sub of due) {
    const notice = await db.priceNotice(sub.id, newPriceId)
    if (!notice || !mayMoveToNewPrice(notice, sub.region)) continue
    await db.scheduleMove(sub.id, newPriceId, sub.currentPeriodEnd)
  }
}
```

### Python example

```python
def migrate_grandfathered(db, old_price_id: str, new_price_id: str, now) -> None:
    for sub in db.subscriptions(price_id=old_price_id, renews_before=now):
        notice = db.price_notice(sub.id, new_price_id)
        if notice is None or not may_move_to_new_price(notice, sub.region):
            continue
        db.schedule_move(sub.id, new_price_id, sub.current_period_end)
```

## Related rules

- PRC-1 [Keep prices in a versioned catalogue](https://agentwranglers.se/playbook/pricing/plans-and-prices/price-catalogue.md) in Pricing, plans and entitlements
- PRC-2 [Tell subscribers before a price rise](https://agentwranglers.se/playbook/pricing/plans-and-prices/price-increase-notice.md) in Pricing, plans and entitlements

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers/grandfathered-prices">Agent Wranglers pricing, plans and entitlements playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Limit the free tier per person instead of per account](https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers/free-tier-abuse.md)
- Next: [Give one trial per person and payment card](https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers/one-trial-per-person.md)
- [Plan changes, trials and free tiers](https://agentwranglers.se/playbook/pricing/plan-changes-trials-and-free-tiers.md)