MacRumors first noted the change in supply.
In the United States, almost all models of the white and black iPhone X can be ordered today for delivery between Dec. 13 and Dec. 15, just 2-5 days from now. This is an improvement since launch, when the iPhone X order page typically said it would ship within a couple of weeks.
The exception appears to be the T-Mobile 128GB and 256GB models, both in black and white, which will be delivered by Dec. 19, according to Apple's website. That's still an improvement and means most orders placed now should arrive before Christmas.
That should alleviate early concerns Apple wouldn't be able to meet demand during the holiday season.