# Subscription payment updates

<a href="https://docs.solidgate.com/billing/subscriptions/subscriptions-1.0/subscription-insights/subscription-events/" target="_blank">Webhooks</a> for subscription status provide real-time notifications about changes in subscription status.
The webhook structure is similar to the subscription status method but additionally includes the `callback_type` parameter in the response object.
There are two versions of <a href="https://docs.solidgate.com/billing/subscriptions/subscriptions-1.0/subscription-insights/subscription-events/" target="_blank">subscription events</a>: legacy and extended.
The extended version offers an enhanced webhook event set with more detail and context, giving merchants deeper insights into subscription stages for better management and analysis.
The legacy version remains supported until the end of August 2026.
<blockquote>
<p>Duplicate webhook events can occur. Implement <a href="https://docs.solidgate.com/payments/integrate/webhooks/#event-handling" target="_blank">idempotency</a> on your end to avoid processing the same event twice.</p>
</blockquote>
Parameters for each callback type can vary based on factors such as product type, payment method, trial availability, or other specific conditions.

Endpoint: POST Billing
Version: 1.0.0
Security: MerchantID

## Header parameters:

  - `merchant` (string, required)

  - `signature` (string, required)

  - `solidgate-event-id` (string, required)
    Unique event identifier.

  - `solidgate-event-created-at` (string, required)
    Event creation time in <a href="https://en.wikipedia.org/wiki/ISO_8601" target="_blank">ISO 8601</a> format with milliseconds.

  - `solidgate-event-type` (string, required)
    Event type, indicating the specific event that occurred.