How do subscription discount/pricing-lock contracts (grandfathered pricing) get preserved when migrating the underlying subscription data to Shopify?

Where does a grandfathered price live in Shopify's subscription model?

A grandfathered price lives on the subscription contract line in Shopify, not on the selling plan. Shopify requires a currentPrice on every line and leaves sellingPlanId optional (Shopify's subscription line reference, October 2026). The plan name even "defaults to using the selling plan's current name when not specified". So the plan describes the offer, and the line records what this subscriber pays. That distinction is easy to miss when you move an active subscription program during a replatform. Import a legacy subscriber at today's list price with a standard plan attached, and you have silently repriced them. The contract looks correct, and the next charge is not.

Which Shopify field carries each kind of price lock?

Each kind of price lock maps to a different Shopify field, and only a fixed line price fits Shopify Subscriptions' contract import, a comma-separated values (CSV) file.

The contract CSV carries a required line price and no discount (Shopify Help Center, October 2026). So a "15% off for life" subscriber imported by CSV becomes a fixed amount. If the percentage itself is the promise, carry it as a manual line discount through Shopify's subscription application programming interface (API). An intro price needs the billing app too: Shopify says a pricing policy "serves as a guide for apps" and "the price of the line item does not update automatically" (Shopify developer docs, October 2026).

What do subscription migration tools drop?

Subscription migration tools can drop the coupons and paused subscriptions that carry price locks, and Recharge's Migr8 tool documents both. Migr8's per-platform tables list coupons as unsupported for every platform it migrates into Recharge: Bold v1 and v2, Stay.ai, Smartrr, WooCommerce, Appstle, Ordergroove and Skio (Recharge Migr8 guide, October 2026). Migr8 also converts "any non-Active subscriptions on your legacy platform" to CANCELLED, so a paused subscriber with a locked price arrives cancelled. A promotional discount that has ridden on a subscription for three years is a coupon, and Migr8 does not carry it. So re-express each lock as a line price or a manual discount, deliberately, before import. Even Shopify's recovery steps for a changed PayPal account warn that a replacement subscription "might not preserve its pricing, discounts, billing cadence, or currency" (Shopify's payment migration page, October 2026).

How do you prove every locked price survived the import?

You prove every locked price survived by reconciling amounts, subscriber by subscriber, before billing moves. Export the destination contracts and compare each next-charge amount with the source platform's last charge, for every subscriber rather than a sample. A subscriber whose amount moved is either a repricing you didn't intend or a lock you failed to carry. Correct each one before the first destination charge. Shopify's contract import requires the first billing date to fall at least 24 hours after the import (Shopify Help Center, October 2026). So leave room between the import and the first charge for this check. The billing anchor and payment token checks run in the same pass.

When should a migration change a legacy price?

A migration should never change a legacy price as a side effect, because in our judgment subscribers read an unannounced change at that moment as a bait and switch.