Hi,
I'm surprised by what you're writing.
The link you provided is not for the API used by the WorldPay payment plugin we provide.
Our plugin is for the Worldpay Business gateway API.
Your link is for the Worldpay eCommerce API. That's another API.
What did Worldpay told you exactly ?
Did they tell you that they'll be shutting down the Worldpay Business gateway API and that you need to switch to the Worldpay eCommerce API ? If that's the case, they should have published some kind of official statement, with dates regarding the evolution of this. Also, it would require the development of a brand new payment plugin, from scratch.
Or did they tell you that if you're using the Worldpay eCommerce API, then the changes made to this API will require adapting the plugin you would be using so far to connect to it ? In that case, this doesn't concern you.