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Given the two terms "obsolete" and "deprecate" in computer science, what is the difference between them?

What I understand,

Deprecated means still available for use but will no longer be developed or supported and may be discontinued in the next release or so.

Obsolete means a better alternative is available so this is now deemed redundant and will probably be discontinued in the next release or so.

It's what I believe and may be incorrect and if so then what is the actual difference?

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The (possible) difference between obsolete and deprecated is explored in this answer and comments thereto. Other than that, the main difference here is simply that deprecate is a verb, but obsolete isn't - so things can't be "obsoleted". – FumbleFingers Oct 23 '12 at 21:12
See also this discussion. – Gnawme Oct 23 '12 at 21:21
This is not an exact duplicate. The other question is, actually, two questions. It puts the question of "obsolete" vs. "deprecated" as an afterthought, and the "extra" question is given very short shrift in the answers. – MετάEd Oct 24 '12 at 0:55
up vote 7 down vote accepted

I don't think that there is a strictly adhered-to distinction enforced within the field of computer science. But in most contexts that I have read, deprecated is more or less a "marker", saying that it should not be used, something else that has the same effect has been created, and it is soon to be deleted. It may still work as expected (read the last paragraph on why I say may), but it will vanish soon. This is intentionally done as part of the software development life cycle when transitioning from one system to another--all of the functionality of the old system is maintained in order to ensure that all past programs still work, and it gives the developers time to transition their code over to the new system.

Obsolete means that it no longer works as expected, or doesn't do anything at all. This is different from non-functional, as it implies that it was rendered so by a new functionality, or its function is simply no longer relevant under the new parameters.

The line between these two terms gets blurred when a function is both deprecated and obsolete. Most of the time, an obsolete function gets deprecated, since it is preferable to deter developers from using it, and to delete it. Since it is generally advisable not to use a deprecated function, whether or not said function is also obsolete is irrelevant, and thus the conflation of the two terms.

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Just a couple of examples: .NET - "The terms obsolete and deprecated have the same meaning"(msdn.microsoft.com/en-us/library/ee461502.aspx), Python "...deprecation is indicated by saying that the module is 'obsolete' or 'deprecated'"(python.org/dev/peps/pep-0004) and JavaScript "...deprecated (that is, still available but planned for removal) and obsolete (that is, no longer usable)" (developer.mozilla.org/en-US/docs/JavaScript/Reference) – tanantish Oct 24 '12 at 10:39
Good explanation of deprecated, although I see more variation in the meaning of obsolete: redundant, deprecated, unsupported, removed. – Bradd Szonye Apr 20 '13 at 21:36

A component that "has been deprecated" is one that is obsolescent. It is fading.

The manufacturer will generally recommend that such a component not be used in new designs, because it is slated to become obsolete (unsupported, perhaps unavailable, perhaps available only at a high price or unfavorable terms) in the not-so-distant future.

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Thanks for this answer, sir. – Tiny Feb 11 '14 at 12:58

Obsolete means out of date or no longer appropriate. In terms of software or features, the word connotes "do not use".

You can still use deprecated features. However, be mindful that they will become obsolete, and may be removed in future.

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