# Adds the trial property to subscription schedule phases

## What’s new

Adds the [trial](https://docs.stripe.com/api/subscription_schedules/object.md?api-version=2026-07-29.dahlia#subscription_schedule_object-phases-trial) boolean property to the [phase configuration](https://docs.stripe.com/api/subscription_schedules/object.md?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) of the [Subscription Schedule](https://docs.stripe.com/api/subscription_schedules/object.md?api-version=2026-07-29.dahlia) object. This property indicates whether a phase is configured as a full trial, meaning the customer isn’t charged during that phase.

Previously, passing `trial=true` and [trial_end](https://docs.stripe.com/api/subscription_schedules/update.md?api-version=2026-07-29.dahlia#update_subscription_schedule-phases-trial_end) together when [updating a Subscription Schedule](https://docs.stripe.com/api/subscription_schedules/update.md?api-version=2026-07-29.dahlia) returned an error because the two parameters were treated as mutually exclusive. You can now pass both parameters together when updating a Subscription Schedule, provided that the value of `trial_end` matches the phase’s end date.

## Impact

If your integration reads a Subscription Schedule object and writes it back to the API in a round-trip pattern, you can now include the [trial](https://docs.stripe.com/api/subscription_schedules/object.md?api-version=2026-07-29.dahlia#subscription_schedule_object-phases-trial) property without removing [trial_end](https://docs.stripe.com/api/subscription_schedules/update.md?api-version=2026-07-29.dahlia#update_subscription_schedule-phases-trial_end). For details about how phases define scheduled subscription changes, see [Subscription schedule phases](https://docs.stripe.com/billing/subscriptions/subscription-schedules.md#subscription-schedule-phases). If you have an existing integration, you don’t need to make any changes.

## Changes

#### REST API

| Parameter | Change | Resources or endpoints |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule.phases[]](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### Ruby

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule::Phase](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### Python

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule.Phase](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### PHP

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule.phases[]](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### Java

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule.phases[]](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### Node.js

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `trial` | Added | [SubscriptionSchedule.phases[]](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### Go

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `Trial` | Added | [SubscriptionSchedulePhase](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

#### .NET

| Parameter | Change | Resources or methods |
| --- | --- | --- |
| `Trial` | Added | [SubscriptionSchedule.Phase](/api/subscription_schedules/object?api-version=2026-07-29.dahlia#subscription_schedule_object-phases) |

## 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.
2. 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: 2026-07-29.dahlia`
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your Ruby SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your Python SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your PHP SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your Java SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your Node SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your Go SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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.
2. Upgrade your .NET SDK to the latest version.
3. Upgrade the API version used for [webhook endpoints](https://docs.stripe.com/webhooks/versioning.md).
4. [Test your integration](https://docs.stripe.com/testing.md) against the new version.
5. If you use Connect, [test your Connect integration](https://docs.stripe.com/connect/testing.md).
6. 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 invoice description, footer, and custom parameters to the Subscription Schedules and Quotes APIs](https://docs.stripe.com/changelog/dahlia/2026-07-29/invoice-description-footer-and-custom-fields.md)
- [Adds subscription metadata support to invoice previews](https://docs.stripe.com/changelog/dahlia/2026-07-29/adds-subscription-metadata-support-to-invoice-preview.md)
- [Adds item-level discount support for pending updates](https://docs.stripe.com/changelog/dahlia/2026-07-29/item-level-discounts-for-pending-updates.md)