Apple is widely expected to move its Mac line to custom ARM-based chips in the coming years.

What we're hearing: Although the company has yet to say so publicly, developers and Intel officials have privately told Axios they expect such a move as soon as next year.

Bloomberg offered a bit more specificity on things in a report on Wednesday, saying that the first ARM-based Macs could come in 2020, with plans to offer developers a way to write a single app that can run across iPhones, iPads and Macs by 2021.

The first hints of the effort came last year when Apple offered a sneak peek at its plan to make it easier for developers to bring iPad apps to the Mac.

Why it matters: The move could give developers a way to reach a bigger market with a single app, although the transition could be bumpy. For Intel, of course, it would mean the loss of a significant customer, albeit probably not a huge hit to its bottom line.

Our thought bubble:

If anything, the Bloomberg timeline suggests that Intel might actually have more Mac business in 2020 than some had been expecting.

The key question is not the timeline but just how smoothly Apple is able to make the shift. For developers, it will likely mean an awkward period of time supporting new and classic Macs as well as new and old-style Mac apps.

History lesson: Apple has already made several big shifts in the 25-year history of the Mac, moving from Motorola chips to PowerPC processors and then to Intel. It's also moved from the classic Macintosh operating system to the Unix-based Mac OS X.