An iPhone 6 Plus or iPhone 6 could run iOS 10 or watchOS 4 but not both, according to a new report from the Wall Street Journal.

Apple has not confirmed the report, but sources told the Journal that a 6 Plus would not work with iOS 10, as it lacks the required Apple Watch apps for notifications and calls.

The Journal reported that Apple’s Apple Watch software could be used to unlock a 6Plus and unlock it with the help of a third-party developer.

A source familiar with Apple’s plans told the Wall Journal that Apple will likely introduce a new version of iOS 10 that will include a “support” section that lets developers build apps for the Watch.

This feature is designed to help Apple differentiate between its more expensive models, which are available in many different versions.

Apple’s iOS 10 release will include support for “Apple Watch” apps, and developers should be able to build support for this feature.

However, a 6 and iPhone 6 users will still have to rely on third-parties for this functionality, so developers need to be careful.

Apple is expected to release an updated iOS 10.3.4 update for the iPhone 6, iPhone 6s and iPhone SE on April 18, but the Apple Watch is expected not to receive this update.