Some Apple retail employees have been told to warn customers against visiting to purchase an iPhone Duo without a pre-order on Friday, October 23. Apple Store employees told MacRumors that they have been advised that there will likely be no ‌iPhone Duo‌ stock available for walk-in purchases on launch day. Staff have been instructed to discourage customers without pre-orders from coming in expecting to buy the device, warning that they will be disappointed. Apple's online store tells customers to check back on Saturday, October 24 for pickup availability. Pickup reservations were briefly available when pre-orders opened before the option was disabled. The October 24 message does not guarantee stock will be available that day, and it remains unclear how firm the warning shared with employees is and whether it applies worldwide. If the guidance is firm and widely perpetuated, it closes off a potential route for customers hoping to bypass the device's lengthy online wait times, at least at the stores concerned. Warnings about a constrained launch began well before Apple announced the ‌iPhone Duo‌. In early September, Nikkei Asia reported that production had reached only a few hundred devices per day in late August. Further production problems emerged in late September. Earlier this month, Bloomberg 's Mark Gurman said Apple had at one point believed production constraints could push the start of sales into November. The company subsequently assembled enough inventory to proceed with the October 23 launch, although supply remained very limited . The extent of the shortage became apparent when pre-orders opened earlier this week.