# Makes flexible billing mode the default for new subscriptions

## What’s new

Newly created subscriptions now default to [flexible billing mode](https://docs.stripe.com/billing/subscriptions/billing-mode.md). You can continue to use `classic` using the [`billing_mode.type`](https://docs.stripe.com/api/subscriptions/create.md?api-version=2025-08-27.preview#create_subscription-billing_mode-type) parameter.

## Why is this a breaking change?

Flexible billing mode has several [differences](https://docs.stripe.com/billing/subscriptions/billing-mode.md#differences-between-classic-and-flexible-billing-mode) over `classic` that change how subscriptions behave and how they calculate invoices.

## Impact

[Flexible billing mode](https://docs.stripe.com/billing/subscriptions/billing-mode.md) provides accurate and predictable billing behavior and additional features for managing subscriptions.

The new default billing mode impacts these integrations:

- [Create a subscription](https://docs.stripe.com/api/subscriptions/create.md?api-version=2025-08-27.preview)
- [Create an invoice preview](https://docs.stripe.com/api/invoices/create_preview.md?api-version=2025-08-27.preview)
- [Create a subscription schedule](https://docs.stripe.com/api/subscription_schedules/create.md?api-version=2025-08-27.preview)
- [Create a quote](https://docs.stripe.com/api/quotes/create.md?api-version=2025-08-27.preview)
- Subscriptions created through the [Checkout Session API](https://docs.stripe.com/api/checkout/sessions/create.md?api-version=2025-08-27.preview)
- Subscriptions created through the [Payment Link API](https://docs.stripe.com/api/payment-link/create.md?api-version=2025-08-27.preview)

## Upgrade

#### REST API

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. If you use an SDK, upgrade to the corresponding SDK version for this API version.
   - If you don’t use an SDK, update your [API requests](https://docs.stripe.com/api/versioning.md) to include `Stripe-Version: 2025-08-27.preview`
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### Ruby

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your Ruby SDK to [v15.6.0-beta.1](https://github.com/stripe/stripe-ruby/releases/tag/v15.6.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### Python

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your Python SDK to [v12.6.0b1](https://github.com/stripe/stripe-python/releases/tag/v12.6.0b1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### PHP

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your PHP SDK to [v17.7.0-beta.1](https://github.com/stripe/stripe-php/releases/tag/v17.7.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### Java

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your Java SDK to [v29.6.0-beta.1](https://github.com/stripe/stripe-java/releases/tag/v29.6.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### Node.js

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your Node SDK to [v18.6.0-beta.1](https://github.com/stripe/stripe-node/releases/tag/v18.6.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### Go

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your Go SDK to [v82.6.0-beta.1](https://github.com/stripe/stripe-go/releases/tag/v82.6.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

#### .NET

1. [View your current API version](https://docs.stripe.com/upgrades.md#view-your-api-version-and-the-latest-available-upgrade-in-workbench) in Workbench.
1. Upgrade your .NET SDK to [v48.6.0-beta.1](https://github.com/stripe/stripe-dotnet/releases/tag/v48.6.0-beta.1)
1. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
1. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
1. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
1. In Workbench, [perform the upgrade](https://docs.stripe.com/upgrades.md#perform-the-upgrade). You can [roll back the version](https://docs.stripe.com/upgrades.md#roll-back-your-api-version) for 72 hours.

Learn more about [Stripe API upgrades](https://docs.stripe.com/upgrades.md).

## Related changes

- [Removes iterations parameter for subscription schedules](https://docs.stripe.com/changelog/basil/2025-08-27/remove_schedule_phase_iterations.md)