United Kingdom, Oct. 19 -- Apple has been caught off guard by demand for the new iPhone Duo, with the company's first foldable iPhone selling out almost immediately after pre-orders opened.

The iPhone Duo, Apple's most dramatic redesign of its flagship smartphone since its launch almost 20 years ago, became available to pre-order last Friday (16.10.26).

Customers who waited as little as half an hour were reportedly told they would not receive their devices until January.

Apple said it was working to increase supplies of the new handset.

Apple told the Financial Times: "The pre-order demand for iPhone Duo, our first foldable iPhone, has been nothing short of extraordinary.

"We are working hard to get this revolutionary new product int...