Apple will have 'limited' iPhone Duo units available in stores on Friday

​Apple ‌on Wednesday said it will have 'limited' numbers ‌of its ‌folding iPhone Duo phone available ⁠for ​walk-in ⁠customers when the ⁠device launches Friday, after ​initial online orders ⁠sold out ⁠in ​minutes and pushed delivery times ⁠for some customers ⁠to ⁠January.