I have a project which was published several months ago. I need to make bug fixing which takes to add several lines of code. After archiving I try to validate and I have error that I have 16-bit or P3 assets, which is strange. Any ideas?
With Xcode 8 GM, this error will occur if you include 16-bit or P3 assets in an app submission targeting iOS releases earlier then iOS 9.3. If your app requires wide color functionality you must change your Deployment Target to iOS 9.3 or later. If your app does not require wide color functionality and you wish to deploy it to older iOS versions then you should replace all 16-bit or P3 assets with 8-bit sRGB assets.
You can see this form.