1 - Download the Swift 5.5.2 toolchain https://www.swift.org/download/ 2 - Install the file 3 - With the project opened, I clicked Xcode -> Toolchains -> selected the one that says "Swift 5.5.2 ". Clean the project and build again.

Doing a little research i found out what is happening. Turns out that the project that I wanted was displaying the error "Module compiled with Swift 5.5.2 cannot be imported by the Swift 5.6 compiler" - different than the question that I made. Here's what I did: 1 - Download the Swift 5.5.2 toolchain https://www.swift.org/download/ 2 - Install the file 3 - With the project opened, I clicked Xcode -> Toolchains -> selected the one that I wanted. Cleaned the project and built again, it worked fine.