accept-migration.mdx

title	accept_migration
description	Accepts a pending plan migration for a subscriber. Cancels the old subscription, creates a new one on the target plan, and sets a fresh token allowance.

fn accept_migration(
    env: Env,
    subscriber: Address,
    sub_id: u64,
    expiration_ledger: u32,
    allowance_periods: u32,
) -> u64

Accepts a pending migration for a subscription. This cancels the old subscription, creates a new subscription on the target plan, and sets a fresh token allowance for the new plan's terms. Returns the new subscription ID.

---

Parameters

Name	Type	Description
subscriber	Address	The subscriber's Stellar address. Must sign the transaction.
sub_id	u64	The old subscription ID with a pending migration.
expiration_ledger	u32	Absolute ledger at which the new SAC allowance expires.
allowance_periods	u32	Number of periods the new allowance should cover.

---

Authorization

subscriber.require_auth();

Only the subscriber on the subscription can accept the migration. The subscriber's signature covers the accept_migration() call, the old subscription cancellation, and the new token.approve() for the target plan.

---

Return value

u64 - the new subscription ID on the target plan.

---

Events emitted

Event	Topics	Data
mig_accept	subscriber, old_sub_id, new_sub_id	Migration details

---

Error cases

Code	Name	Description
9	Unauthorized	Caller is not the subscriber on this subscription.
12	NoMigrationPending	No migration has been requested for this subscription.

---

Examples

```typescript import { VowenaClient, NETWORKS } from "@vowena/sdk";

const client = new VowenaClient({
  contractId: NETWORKS.testnet.contractId,
  rpcUrl: NETWORKS.testnet.rpcUrl,
  networkPassphrase: NETWORKS.testnet.networkPassphrase,
});

// Accept the pending migration
const tx = await client.buildAcceptMigration(
  "GSUBSCRIBER...ADDR",   // Subscriber's address
  oldSubscriptionId,       // Old subscription ID
  { allowancePeriods: 24 } // Optional allowance tuning
);

const signedXdr = await signTransaction(tx);
const result = await client.submitTransaction(signedXdr);
console.log("New subscription ID:", result.subscriptionId);
```

```bash soroban contract invoke \ --id CONTRACT_ID \ --network testnet \ --source SUBSCRIBER_SECRET \ -- \ accept_migration \ --subscriber GSUBSCRIBER...ADDR \ --sub_id 1 \ --expiration_ledger 3100000 \ --allowance_periods 24 ``` The new subscription inherits the subscriber's billing history context but starts fresh on the new plan's terms. The old subscription is permanently cancelled. The new allowance is calculated based on the new plan's `price_ceiling` and `max_periods`.