You can discourage people from using it while still maintaining compatibility. I have a Go library with some functions that have been deprecated since Go 1.1 (

You can discourage people from using it while still maintaining compatibility. I have a Go library with some functions that have been deprecated since Go 1.1 (2013); they're just some aliases or wrappers for the newer symbols. They will stay there forever until I have enough reason to release a v2 (which may be never). POSIX also includes plenty of legacy/deprecated stuff like mktemp() that will likely never be removed. A CLI is a public interface; breaking compatibility is kinda bad.