# Adds support for third-party tax on flexible billing mode subscriptions

## What’s new

Allows you to use [third-party tax apps](https://docs.stripe.com/tax/third-party-apps.md) to calculate tax for subscriptions configured with [flexible billing mode](https://docs.stripe.com/billing/subscriptions/billing-mode.md).

## Impact

Creating and updating flexible billing mode subscriptions completes successfully and no longer returns a `400` error code while using a third-party tax app.

## 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.basil`
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 [v15.5.0](https://github.com/stripe/stripe-ruby/releases/tag/v15.5.0)
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 [v12.5.0](https://github.com/stripe/stripe-python/releases/tag/v12.5.0)
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 [v17.6.0](https://github.com/stripe/stripe-php/releases/tag/v17.6.0)
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 [v29.5.0](https://github.com/stripe/stripe-java/releases/tag/v29.5.0)
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 [v18.5.0](https://github.com/stripe/stripe-node/releases/tag/v18.5.0)
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 [v82.5.0](https://github.com/stripe/stripe-go/releases/tag/v82.5.0)
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 [v48.5.0](https://github.com/stripe/stripe-dotnet/releases/tag/v48.5.0)
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

- [Adds a name field to the customer portal configuration object](https://docs.stripe.com/changelog/basil/2025-08-27/customer-portal-config-name.md)
- [Adds support for invoice items metadata and period in subscriptions and schedules](https://docs.stripe.com/changelog/basil/2025-08-27/add_invoice_items_metadata_and_period.md)