https://www.techradar.com/news/apple-watch-4-appears-to-be-referenced-in-latest-ios-12-beta

Apple didn't officially confirm the Apple Watch 4 today, but it gave us a big hint that it's actively working on a new iPhone-compatible smartwatch.

Its iOS 12 developer beta 2 software just launched, and inside the code are new identifiers Watch4,1, Watch4,2, Watch4,3 and Watch4,4, according to 9to5Mac.