Shopify Marketplace Connect

For a core Shopify app this is not well supported. Be warned it will only match the first 100 product variants in a family, the rest won't sync. Support doesn't seem willing to upgrade their systems to support the now 2,000 variants you can have. The fact that Shopify promotes that you can sell on Marketplaces but doesn't give you a fully function app feels like misleading advertising to me.