The four-figure iPhone X with face-recognition technology and Super Retina display — is not selling as well as the iPhone 8 and the iPhone 8 Plus together.

Apple sold more of the $699 iPhone 8's in the U.S. and in Europe's top five markets than the $999 iPhone X, according to the British-based data firm, Kantar and reported by 9to5Mac.

Poor sales of the iPhone X — Apple's most expensive iPhone — dovetail with rumors that Apple is planning to say goodbye to its newest iPhone this fall, and instead launch a completely new version. Normally, Apple keeps its newest phone in the lineup, just dropping it down in the line-up — along with the price. This year, however, analyst Ming-Chi Kuo of KGI Securities, believes that Apple will release two new iPhones, and discontinue the iPhone X completely.

Apple has been fighting sluggish sales since launching the iPhone X in November, even making a decision in January to reportedly cutting the production of the phone in half. Apple's original goal of selling 50 million iPhones for the first quarter dropped to just 20 million. Sales for its iPhone 8 and iPhone 8 Plus, however, stayed on target.

Still, on Apple's earning report this week, CEO Tim Cook stated that more iPhone X's are sold every week than any other Apple device — and that iPhone sales have increased 3 percent from the year prior.