Latest Xcode does not support Swift 3 (use Xcode 10.1)

The latest Xcode(10.3) does not support our Swift 3 project

We have to use Xcode 10.1 to migrate to Swift 4. I'm not sure if Xcode 10.1 will also run our project (will have to downgrade)

Remediation

Use Xcode 10.1 to migrate the codebase to Swift 4