According to analyst Ming-Chi Kuo, Apple will only release a USB-C case for the AirPods Pro 2 and not for other versions.
AirPods Pro case
The company recently issued the release candidate version of iOS 16.4 and other operating systems. The code suggested that new AirPods are on the way with the model number A3048, and a new AirPods case numbered A2968.
On Friday, Kuo tweeted that it likely refers to a USB-C version of the second-generation AirPods Pro, with mass shipments expected in the second to third quarter. However, he added that Apple has no current plans for USB-C versions of the AirPods 2 and AirPods 3 generations.
I think this is likely the USB-C version of the AirPods Pro 2, with mass shipments expected in 2Q23-3Q23. By the way, Apple currently appears to have no plans for USB-C versions of the AirPods 2 & 3.
-- (Ming-Chi Kuo) (@mingchikuo) March 24, 2023
AirPods Pro https://t.co/aWKJvGh1lW
The switch to a USB-C port is due to rules from the European Union that requires Apple and other companies to use USB-C in their devices by 2024. Apple includes the port in newer Macs and iPads, but not the iPhone with its Lightning port.
Specific iPhone 15 models may include a USB-C port, but Apple doesn't technically have to comply until December 28, 2024. But iPhones must have the port starting with the iPhone 17.