Jordan Kahn, writing for 9to5Mac:

It would be fine if all of those USB-C accessories you purchased for your 2015 MacBook were firmware upgradeable and received updates like Apple’s own products, but many of them are not. So if you have accessories purchased for the 2015 MacBook, there is a good possibility they won’t work with your 2016 MacBook or any other new USB-C device. Accessory makers also tell me Apple changed power protocols in the 2016 MacBook meaning 5W-12W battery packs that could be used with the 2015 model over USB-C no longer work with the new 2016 model now requiring at least 18W. And if you grab a USB-C cable or other accessory, don’t expect it to just work with your Mac. Not such a great situation for a standard that’s supposed to, you know, standardize compatibility of products using the spec.

Wow. If and when Apple does release a new MacBook Pro that relies on USB-C ports, will this complicate the problem further? Will I need to mark my cables with the device for which they were designed? Will my MacBook Pro not be able to charge using a MacBook 2016 charger?