Just got my Christmas present from Shopify:

You have 45 days to integrate with our new Billing API or lose your app on our app store.

Because I just LOVE dropping everything to deal with yet another mandatory Shopify change. Have you guys not heard of backwards compatibility?

My coworker just spent *weeks* getting our app approved, including submitting an obscene amount of information and multiple live reviews and now they're threatening to remove our listing from their app store if we don't adopt their new API by the end of January, requiring a complete re-submission and review to get it back on.

This is apparently a completely normal way to do business to Shopify.