Apple’s highly anticipated iPhone Duo is set to arrive in stores on Friday, October 23, but customers hoping to purchase the company’s first foldable smartphone without a pre-order could be left disappointed as supply shortages continue to affect availability.

According to a report from MacRumors, some Apple Store employees have been instructed to discourage customers from visiting stores on launch day without a reservation, with little or no stock expected to be available for walk-in purchases.

Apple’s online store is also advising customers to check back on October 24 for in-store pickup availability, although this does not guarantee that additional devices will be available. It remains unclear whether the reported restrictions apply to Apple Stores worldwide or only in selected markets.

The limited availability follows an overwhelming response to iPhone Duo pre-orders, which reportedly sold out almost immediately after opening.

Delivery estimates began slipping within minutes, and just half an hour after pre-orders went live, every configuration listed on Apple’s online store was showing an estimated shipping date of January 25.

That means customers ordering the device now could face a wait of more than three months, potentially missing out on receiving the foldable iPhone before Christmas.

While strong demand appears to be contributing to the shortage, Apple has also reportedly encountered significant manufacturing difficulties in the lead-up to the launch.

In September, Nikkei Asia reported that production of the iPhone Duo was limited to just a few hundred units per day in late August, with further complications emerging as the company attempted to increase manufacturing volumes.

The device’s complex folding design has reportedly created additional challenges for Apple’s suppliers, including difficulties with the hinge assembly and production yields for its foldable OLED display.

Bloomberg’s Mark Gurman also reported that Apple had considered postponing the iPhone Duo’s release until November because of supply constraints, before ultimately securing enough inventory to proceed with its planned October launch.

Despite the production difficulties, Apple appears encouraged by the initial response to its first foldable smartphone.

In a statement to the Financial Times, the company described demand as “nothing short of extraordinary” and said it was working to get devices into customers’ hands as quickly as possible.

However, Apple has not officially confirmed whether any of its retail stores will have iPhone Duo stock available for customers without pre-orders when sales begin on Friday.

Starting at $3,499, the iPhone Duo represents Apple’s long-awaited entry into the foldable smartphone market, although its limited availability could make it one of the company’s most difficult new products to purchase.

With online shipping estimates already extending into late January, customers hoping to secure an iPhone Duo on launch day may have little choice but to rely on existing pre-orders or monitor Apple’s website for any additional in-store availability.