Apple is encouraging participants of its iPhone Upgrade Program to be prepared for the release of the iPhone X, inviting customers to go through a pre-approval process for the upgrade a few days before it ships on October 27.

The iPhone Upgrade Program website reveals it will be allowing customers enrolled in the scheme to go through the upgrading process from October 23 to October 26, in order to approve as many eligible customers as possible ahead of when the iPhone X will become available to purchase. A notice advises users to prepare for the pre-order via the Apple Store app to "speed through checkout" on Oct. 27.

The pre-approval process for the iPhone X echoes a similar notification sent out by email to customers a few days before the iPhone 8 shipped. Just as with the iPhone X, the iPhone 8 notification suggested customers got "all the prep work done" days before its release, and to use the Apple Store app to save time during the ordering process.

There was some concern about whether there would be a pre-prep process for iPhone Upgrade Program members for the iPhone X, partly due to the expected high popularity for the device, as well as supply chain and analyst reports suggesting there to be production bottlenecks. It has also been suggested Apple is stockpiling between 2 and 3 million units in preparation for launch to mitigate the bottlenecks.

Program participants can check through the iPhone Upgrade Program website for eligibility, after signing in with an Apple ID or entering the relevant details into the web-based form. The App Store iOS app may be a quicker and easier process, as it is capable of scanning the device's serial number and IMEI automatically.