message: String,
    replaceWith: ReplaceWith = ReplaceWith(""),
    level: DeprecationLevel = DeprecationLevel.WARNING)

Marks the annotated declaration as deprecated.

A deprecated API element is not recommended to use, typically because it's being phased out or a better alternative exists.

To help removing deprecated API gradually, the property level could be used. Usually a gradual phase-out goes through the "warning", then "error", then "hidden" or "removed" stages:

  • First and by default, DeprecationLevel.WARNING is used to notify API consumers, but not to break their compilation or runtime usages.
  • Then, some time later the deprecation level is raised to DeprecationLevel.ERROR, so that no new Kotlin code can be compiled using the deprecated API.
  • Finally, the API is either removed entirely, or hidden (DeprecationLevel.HIDDEN) from code, so its usages look like unresolved references, while the API remains in the compiled code preserving binary compatibility with previously compiled code.