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    Deprecated or deprecation is the discouragement of the use of a programming language feature. It should not be confused with depreciation, which is the monetary devaluation of goods over time.

    What does deprecation mean?

    Deprecation is a term primarily used in the fields of software engineering and programming to indicate that the use of a certain software feature or programming language feature has been superseded. Deprecation indicates that the software or code feature is still tolerated or supported, but its use is not recommended.

    Deprecated code typically has not yet been removed, but deprecation implies that the code may be removed in the future. An alternative, superior software feature is generally recommended when code is announced as deprecated. Deprecation can have a strong impact on software ecosystems.

    The term is also used in a similar fashion in hardware design, technical standards, and other technical or scientific fields.

    Code is announced as deprecated in different ways depending on the situation and the organization. Designation usually takes the form of an annotation or tag within the code noting the deprecation and the recommended replacement and is often more broadly announced in a publication, forum, repo or other channels.

    Why is code deprecated?

    Code that has been deprecated can be discouraged from being used for a number of reasons.

    • Use of another software feature is recommended or encouraged due to being considered superior, such as being more efficient.
    • The software feature contains a design flaw, such as a bug or security flaw, but existing code is still dependent on it.
    • The feature is deemed unnecessary and is earmarked for removal in order to simplify the system.
    • It is expected that structural changes made in a future version of the software will make the deprecated software features impractical or impossible to support.
    • To eliminate inconsistencies and ensure compliance with standards or naming conventions.
    • Multiple features have been combined, rendering one or more of the individual features obsolete.
    • The deprecated code encourages and supports coding practices that are obsolete or have been replaced by new best practices.

    Why Isn’t deprecated code removed iImmediately?

    Deprecated code is not removed immediately because doing so would cause malfunction in existing code, and could disrupt plans and predictability in coding and business projects, leading to losses.

    Leaving deprecated code temporarily available gives programmers time to bring old code up to compliance with the new standard. It also gives programmers time to replace existing code that is dependent on the deprecated code, preventing sudden shifts in project priorities and backward compatibility issues.

    When is deprecated code removed?

    The timeline of code removal varies by organization and situation. Code designated as deprecated may or may not work after deprecation, but it is no longer guaranteed to work or be supported. Deprecation may urgently imply that users should switch to the new software code solution as soon as possible, even if no removal timeline is given.