What vendors mean by deprecated, sunset and legacy
Deprecated usually means still running, do not build new things on it. Sunset usually means a date exists. Legacy often means nothing at all. None of these words carries a guaranteed meaning, and only one of them implies a date. As of 2026-09-12.
| Word | Usually implies |
|---|---|
| Deprecated | Still works, no longer recommended |
| Legacy | Still available, not developed further |
| Retired | No longer available |
| Sunset | A date exists, published or not |
Inclusion rule. Usage as it recurs across vendor announcements. No vendor publishes a glossary of these terms, so none of them are definitions. Order. Alphabetical by word.
1Deprecated
Borrowed from software, where it means a feature still works and is no longer recommended. Applied to a model it usually signals the same: available today, not the thing to start new work on, and likely to be removed eventually.
Crucially it does not imply a date. A model can sit deprecated for a long time, and treating the word as a countdown produces panic migrations that were not necessary.
2Sunset
The word most often attached to an actual date, and the one worth searching for in a vendor's changelog. When a company says sunset, they usually mean there is a calendar entry, and the useful follow-up question is which surfaces it covers.
A model can be sunset in a consumer app while remaining available through an API, or the reverse. Those are different dates and coverage routinely reports only the first.
3Legacy
The weakest of the three. It usually describes a tier or model kept for existing customers, with no statement about how long. Sometimes it means frozen but supported; sometimes it is the label applied a month before removal.
If a product you depend on has been moved to a legacy label, that is a prompt to ask rather than a signal to act. The word alone supports neither reassurance nor alarm.
4End-of-life
The most definite term in common use, borrowed from hardware. It normally means a stated date after which the thing does not run. Where a vendor uses it, expect a date and treat its absence as worth chasing.
It is also the rarest of the four in this field, which tells you something about how mature the practice of retiring models currently is.
5What none of them tell you
Whether output generated on the version stays reproducible. A model can remain available and still change: the same prompt with the same seed can produce something different after an update that carried no announcement at all.
That is the failure mode a retirement vocabulary does not cover, and for a series in production it is more disruptive than a removal, because nothing marks the moment it happened.
6Where to look rather than what to read
Changelogs and developer documentation carry dates; marketing pages carry adjectives. A vendor with a dated changelog is giving you something to plan against even when the news is bad.
For models reached through an app rather than directly, the app's own pages are usually silent and the maker's are not. Follow the model name upstream rather than waiting for the reseller to mention it.
7Preview, beta and experimental
At the other end of the life cycle, these labels signal a model that may change without notice and may never reach general availability. Building a series on one is a decision, not an accident, and it is worth naming as such at the start.
The practical rule most teams settle on is that preview models are fine for exploration and for anything with a short life, and unsuitable for a run of episodes that has to look the same in twelve months.
8Silence is the most common status of all
Most models in this field carry no status word at all. They are simply available, with no page describing what happens when they stop being. That is the normal state and it should be read as an absence of information rather than a commitment.
Which is why the bookkeeping matters more than the vocabulary: a record of what you used is something you control, and a vendor's choice of adjective is not.
9How to record this for your own team
One line per model you depend on: the maker, the version, where you read its status, the word they used, and the date you checked. Re-read quarterly.
That takes minutes and it converts a vague unease about model churn into a short list somebody can act on. It is also the only form of early warning available to a production, because the companies that have committed to a notice period sell to developers rather than to productions.
Guidance rather than a dated entry. No line here is a vendor statement, and none should be read as an announcement. The sourced material is on the calendar. Related: Reading a lifecycle page, Recording per file.