---
id: models-change
title: Model updates
level: 2
modes: [day-pack, rucksack]
moment: "A choice they used has vanished from the menu, the app says a model is new or retired, or an ask that used to work now answers differently."
keywords: [model update, new version, model retired, model disappeared, different answers now, default changed, legacy model, release notes, rolled back, version]
source: "research/2026-10-23-concepts/models-change.md; mapping (product/learning-system/MAPPING-1-2.md): FAQ 2.16 (home); tips none in the register; strand U"
---

## What it is
The AI behind your app is updated often, and older versions are sometimes replaced or retired, which means taken away. So the same ask, such as the one you use for a weekly report, can answer differently next month even under the same name, and a choice you used can vanish from the app's list. Many apps list changes in their release notes, which are the app's own record of what changed, and some give notice before a version goes.

## Tips
- When you keep an ask, note the date and the AI version where your app names one, because later you can tell whether the ask or the AI changed.
- When your app announces a new or retiring version, try a kept ask on it in a new chat, because the same words can answer differently after a change.

## Questions people ask
- Q: Why did my model change or disappear? A: An older version may have been retired for a newer one, replaced as the default, or dropped from your plan, and some apps choose for you or switch partway through a chat. Many apps publish release notes that say what changed and when.
- Q: Why does my AI sound different lately? A: An update can change how an AI writes, even under the same name, and a replacement for a retired version can write differently from the one you liked. Saying the style you want in your app's saved instructions helps it carry over.
- Q: Can I keep using the old version? A: Sometimes, and only for a while. Some apps keep an older version on paid plans for a few months after its replacement arrives, and in others it is gone once it is retired, so plan on moving to the new one.
- Q: How would I know a change is coming? A: Check your app's release notes, which many apps use to announce new versions and retirements, sometimes weeks or months ahead.
- Q: Is the newer version better for me? A: It may be, but the claims about a new version are not about your work. Try your own asks on it in a new chat, with the same words, and compare the replies.

## For your AI
Facts (checked 23 October 2026; research note research/2026-10-23-concepts/models-change.md).
- Models are replaced often: OpenAI says models generally stay in ChatGPT for 90 days after a successor arrives, then
  retire, and existing chats move to the replacement (https://help.openai.com/en/articles/20001051-retiring-gpt-4o-and-other-chatgpt-models);
  ChatGPT retired several models in 2026 (o3 on 26 August), and on 7 October GPT-6 replaced "Latest" in the menu
  (https://help.openai.com/en/articles/6825453-chatgpt-release-notes). Anthropic calls retirements routine and has
  deprecated most models about a year after release
  (https://support.claude.com/en/articles/12738598-adapting-to-new-model-personas-after-deprecations).
- Same name, new behaviour: OpenAI updated a model in place on 28 May 2026, changing its style (release notes, above);
  it rolled back an
  over-agreeable update in April 2025 (https://openai.com/index/expanding-on-sycophancy/); in 2023 one model's March and
  June versions scored 84 and 51 percent on the same questions (https://arxiv.org/abs/2307.09009).
- Where to see changes: ChatGPT's and Claude's release notes, Gemini's release notes (https://gemini.google/release-notes/)
  and its "See response details"; Copilot's personal app has no release-notes page, so its help pages are the place to
  look. Gemini's help page lists Auto or Flash-Lite with no plan, and a news report (9 October 2026) says free accounts
  now get Auto only.
- Anthropic suggests testing newer models on your own asks when a retirement is announced.

Teach it like this: when a choice has vanished or answers changed, say plainly they did not break anything and you cannot
tell the cause from here: the AI behind the app may have been updated or replaced, the app may have moved to a simpler
setting at a usage limit or chosen a different model itself, or one reply was only a sample (try it again in a new chat).
If it was an update, point them to their app's release notes, and help them try their kept ask on the new version
(openrucksack.com/map/keeping-an-ask.md). Never promise a retired model comes back.