> ## Documentation Index
> Fetch the complete documentation index at: https://docs.aftersell.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Subscription upgrades limitations & important notes

Review these constraints and behaviours before you launch a Subscription Upgrade funnel. They explain the edges of what the feature can and cannot do, and prevent the most common surprises.

## Important notes

* **One subscription change per post-purchase flow.** Only one subscription offer can be accepted per post-purchase page. If your funnel has multiple subscription-related steps, only the first accepted offer goes through. The funnel editor warns when it detects this conflict.
* **Subscriptions only.** This feature only fires when the customer's order contains the subscription version of the eligible product. It will not fire for one-time purchases of the same product.
* **Frequency on replacements.** When using **Replace with a different subscription product**, the new item inherits the original subscription's frequency unless you also pick **Change frequency and replace product**.
* **Multi-product upsells.** Subscription upgrade settings are configured per product. If you are offering multiple products in one upsell, configure each individually.
* **Recurring discount applies to every future renewal.** Unlike a one-time discount, this stays in effect on every renewal of the upgraded subscription.
* **Prepaid conversion with partial credit is not supported.** If a customer already paid for part of a prepaid cycle, Aftersell cannot pro-rate the remaining shipments. Replacement upgrades charge the full new subscription and refund the original.

## Provider-specific limitations

Each subscription platform behaves a little differently. Loop in particular has the most constraints (postpaid only, selling plans must pre-exist, up to a 24-hour sync delay). For the full per-provider details, see the integration guides:

* [Recharge](/aftersell/subscription-upgrades-recharge)
* [Skio](/aftersell/subscription-upgrades-skio)
* [Loop](/aftersell/subscription-upgrades-loop)

## Related

* [Setup & configuration](/aftersell/subscription-upgrades-setup)
* [Fulfillment & 3PL mapping](/aftersell/subscription-upgrades-fulfillment)
* [Troubleshooting](/aftersell/subscription-upgrades-troubleshooting)