Makes sense, since both macOS and iOS have been moving to 64-bit-only and will be giving the same warnings.Well, we shouldn't exactly call them new features, because chief among the newcomers is simply a pop-up warning that older apps will start working with unspecified future versions of the system, probably watchOS 5. The alert states that "This app will not work with future versions of watchOS. The developer of this app needs to update it to improve its compatibility."
And the 9to5Mac page that Engadget referenced (or copy-pasted from) was updated later:
And this, from The Mac Observer, who also quoted Troughton-Smith:Update (4/16): Steve Troughton-Smith warns that this might not be what it looks like:
…haven’t third-party watch face config bundles been a thing for years? I wouldn’t get too excited about a log message just yet https://t.co/Ms1pyhPaAG https://t.co/EPbSbuceD6
— Steve Troughton-Smith (@stroughtonsmith) April 16, 2018
He also linked to Apple’s developer article about adding complications to the watch face gallery—something developers have been able to do for some time, and very likely exactly what the line of code is referencing.
It’s easy to see which apps support Apple Watch complications in the Watch app on your iPhone. Just tap My Watch in the Watch app, then tap Complications. From there you can see a list of every app with an available complication.