Which version of XCode are you using? Please attach the log of the errors you are seeing so that we can get more insight on the issue.
I used the latest version at the beginning and it does not support Swift Complier- language : "Swift 3". So then, I tried with Xcode 10.1, Which supports Swift 3. But it says it can not support building or migrating Swift 2.x targets. It wants me to use Xcode 8.x. Now the problem is Xcode 8.x is not compatible with macOS Catalina. What should I do?
The latest version of Cysmart source code has been developed using XCode 10.1. Please download the source code from here: https://www.cypress.com/documentation/software-and-drivers/cysmart-mobile-app
I think you might have downloaded an older source code which targets Swift 2.x and hence the error.