No, you cannot send binary code containing code generated using the Swift 4 toolchain (or any other development toolchain) to the Apple App Store using Xcode 8.3.2.
Jordan Rose, Apple Swift Compiler Engineer, Twitter :
Tool chain development is never used when shipping to the store, sorry! (We want to avoid scripts like XcodeGhost.)
Therefore, this configuration is not supported, and you will need to wait for Xcode 9 to submit projects using Swift 4. Your binary will be rejected.
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