# CMAKE_TLS_VERSION

Added in version 3.30.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Specify the default value for the `file(DOWNLOAD)` and `file(UPLOAD)` commands' `TLS_VERSION` option. This environment variable is used if the option is not given and the `CMAKE_TLS_VERSION` cmake variable is not set. See that variable for allowed values.

This variable is also used by the `ExternalProject` and `FetchContent` modules for internal calls to `file(DOWNLOAD)` and `git clone`.