I'm using the Paypal Express Checkout NVP (Name Value Pair) API. When I add a Callback URL for instant update shipping cost the whole paypal user interface changes to an older version that isn't mobile friendly / responsive.
When I try to force the mobile UI with "_mobile-express-checkout" I'm getting an Error-Message that I'm using an outdated version. But I'm using version 204 that is the most up to date version.
Is there any chance to get the responsive layout together with instant update for shipping cost?