Finding Swift files that need to be migrated

Using Swift
1

In Xcode I get a warning when opening my project:

The target "XYZ” contains source code developed with Swift 3.x. This version of Xcode does not support building or migrating Swift 3.x targets.

I can't however find which Swift files need to be migrated. Here's what I have done:

find . | grep -i "\.swift$" | while read l; do swiftc -parse -swift-version 5 "$l"; done

and

find . | grep -i "\.swift$" | while read l; do swiftc -parse -runtime-compatibility-version 5.0 "$l"; done

Both commands terminate without error.

Doesn't this mean that in fact all my swift files are written for the latest Swift?

If not, what can I do?

I should also mention: Xcode builds the app just fine. It's just that warning that irritates me.

P.S.: I can't migrate because the required Xcode version 10.1for some reason will not launch.

2

You can change the ‘Swift Language Version’ build setting to Swift 5 to tell Xcode that the sources have been migrated already.