Swift_LANGUAGE_VERSION

This property sets the language version for the Swift sources in the target. If one is not specified, it will default to <CMAKE_Swift_LANGUAGE_VERSION> if specified, otherwise it is the latest version supported by the compiler.

© 2000–2020 Kitware, Inc. and Contributors
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.17/prop_tgt/Swift_LANGUAGE_VERSION.html