Checkout extension on New Dev Stores

Extensions
1

I created checkout UI.

It works on
1.old dev stores.
2. Theme editor.
3. Preview.

When saving, it says error. “The extension cannot be activated at this extension target.”

Why?

2

Hi @Dinesh_Dahal

It’s not easy to explain why this behaviour is happening with the level of detail provided but can you:

  1. Verify the new dev store was created with “Developer preview” as the build version?

  2. Confirm you’re using the modern target names (e.g., purchase.checkout.block.render, not Checkout::Dynamic::Render)

  3. If targeting specific checkout steps (information/shipping/payment), ensure the dev store has Shopify Plus features (dev stores typically do, but configuration matters)

  4. Try scaffolding a fresh extension with shopify app generate extension --template checkout_ui to ensure the latest api_version and config format