update_plan_amount

fn update_plan_amount(env: Env, plan_id: u64, new_amount: i128)

Updates the per-period billing amount of an existing plan. The new amount must be positive and must not exceed the plan’s price_ceiling. This allows merchants to adjust pricing without requiring subscribers to re-authorize.

Parameters

Name	Type	Description
`plan_id`	`u64`	The ID of the plan to update.
`new_amount`	`i128`	The new billing amount per period, in stroops.

Authorization

merchant.require_auth();

The merchant address stored on the plan must sign the transaction.

Return value

None (void).

Events emitted

Event	Topics	Data
`plan_updated`	`plan_id`, `new_amount`	Updated plan details

Error cases

Code	Name	Description
6	`PlanNotFound`	No plan exists with the given `plan_id`.
3	`InvalidAmount`	`new_amount` is zero or negative.
10	`AmountExceedsCeiling`	`new_amount` exceeds the plan’s `price_ceiling`.

Examples

SDK
Soroban CLI

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

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

// Raise the price from 9.99 to 12.99 (within the 14.99 ceiling)
const tx = await client.buildUpdatePlanAmount(
  planId,                   // Plan ID
  toStroops("12.99")        // 129900000n stroops
);

const signedXdr = await signTransaction(tx);
await client.submitTransaction(signedXdr);

soroban contract invoke \
  --id CONTRACT_ID \
  --network mainnet \
  --source MERCHANT_SECRET \
  -- \
  update_plan_amount \
  --plan_id 1 \
  --new_amount 129900000

Since the token allowance is set against the price_ceiling (not the current amount), updating the amount within the ceiling does not require subscribers to re-authorize. All existing subscriptions will be charged the new amount on their next billing cycle.

If you need to set a price above the current ceiling, you must create a new plan and use the migration flow to move subscribers. This ensures subscribers always have explicit control over their maximum exposure.

Overview

Core

Management

Migrations

Read-only

Utilities

update_plan_amount

Parameters

Authorization

Return value

Events emitted

Error cases

Examples

​Parameters

​Authorization

​Return value

​Events emitted

​Error cases

​Examples

Parameters

Authorization

Return value

Events emitted

Error cases

Examples