Technology

Apple’s first foldable smartphone, the iPhone Duo, went on sale Friday after pre-orders pushed estimated delivery dates into late January within minutes of opening. Apple capped pre-orders at two devices per customer and restricted walk-in availability, with purchases in several markets limited to customers who had ordered online.

The $1,999 handset combines a 5.4-inch outer OLED display with a 7.6-inch folding inner screen. Engadget praised both displays, the device’s sturdy construction and a crease that is difficult to notice during normal use, but found the Duo heavier than competing foldables. Its review also noted that the inner screen’s replaceable nanotexture layer can be removed if picked at too much and that Apple does not warn users during setup not to remove it.

Early reviews cited by Dawn praised the Duo’s design and barely visible hinge while identifying compromises …