In a blog post, Apple has warned developers that all watchOS apps need to be native apps by April 1.
Apple will no longer be accepting updates to watchOS 1 apps after that date, meaning all submissions will have to be built with the watchOS 2 SDK or later, and new apps “should be built with the watchOS 4 SDK or later.” It appears that existing non-native apps will likely still remain on the App Store after April 1, 2018, however developers will not be able to release updates to those apps without rebuilding them with the newer watchOS2 SDK.
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