AI model release tracker: what changed in each engine?
Broadcastwell measures and fixes whether AI search engines name B2B software companies.
Run the free checkThis AI model release tracker lists the model releases that the providers behind ChatGPT, Claude, Perplexity, Google AI Overviews and Google AI Mode dated on their own public pages between 1 July and 9 November 2026. Each row gives the release in the provider's words, the date the provider published and the page we read. A release is a dated mark on our time series, never an explanation of a change in answers.
Updated 11 November 2026.
We read every source below on 9 November 2026. Release names are quoted as each provider wrote them. Where a provider names the plans or surfaces a release reaches, we repeat that scope; where it does not, we say so rather than guess. We make no forecast of future releases.
ChatGPT: OpenAI
Source: OpenAI Help Center, ChatGPT release notes, read 9 November 2026.
| Date published | Release, in OpenAI's words | Scope OpenAI states |
|---|---|---|
| 6 August 2026 | "Updates to GPT-5.6 in ChatGPT" | An updated GPT-5.6 Sol for Plus and Pro; GPT-5.6 Luna to become the default model for Free and Go users "this week". The chat experience only. |
| 3 September 2026 | "Introducing GPT-6 Astra" | Rolling out first to "a limited set of organizations". |
| 22 September 2026 | "GPT-6 Sol and Luna in Work and Codex" | ChatGPT Work and Codex, "separate from the models available in Chat". |
| 29 September 2026 | "GPT-6.1 Sol in ChatGPT Work and Codex" | ChatGPT Work and Codex, starting with Pro users. |
| 7 October 2026 | "GPT-6 and Intelligent UI in ChatGPT" | The Chat tab. Plus, Pro, Business and Enterprise use GPT-6 Sol; Free and Go use GPT-6 Luna, with Free and Go starting the following day. |
| 26 October 2026 | "GPT-6.1 Terra" | ChatGPT Work and Codex. |
Claude: Anthropic
Sources: Anthropic support center, Claude release notes, and the Anthropic newsroom, both read 9 November 2026.
| Date published | Release, in Anthropic's words | Scope Anthropic states |
|---|---|---|
| 24 July 2026 | "Claude Opus 5 launch" | The release note names no plan-by-plan default. |
| 1 September 2026 | "Claude Fable 5.1 and Claude Mythos 5.1 launch" | The release note names no plan-by-plan default. |
| 22 September 2026 | "Claude Opus 5.5 launch" | Described as "the first model in our new Claude 5.5 family". |
| 28 September 2026 | "Claude Sonnet 5.5 launch" | Described as "the second model in our Claude 5.5 family". |
| 7 October 2026 | "Claude Haiku 5.5 launch" | Described as designed "for high-volume, cost-sensitive tasks". |
Perplexity
Source: Perplexity changelog, read 9 November 2026. Perplexity offers models from other providers inside its own product. Its changelog names the models it added; it does not say which model answers a signed-out search.
| Date published | Changelog entry, in Perplexity's words | Models the entry names |
|---|---|---|
| 27 July 2026 | "Role-based access controls, API credentials, and Brain for Max" | Opus 5 |
| 24 August 2026 | "Computer in Email, GPT-5.6 Terra and Luna, and Grok 4.6" | GPT-5.6 Terra, GPT-5.6 Luna, Grok 4.6 |
| 21 September 2026 | "Effort Mode, GPT-6 Astra, and Skills Marketplace" | GPT-6 Astra |
| 5 October 2026 | "Automations, inline visualizations, and GPT-6.1 Sol" | GPT-6.1 Sol, Claude Opus 5.5 |
Google AI Overviews and Google AI Mode: Google
Sources: Gemini Apps release notes and the Google blog posts linked in each row, read 9 November 2026. Google AI Overviews and Google AI Mode are separate products, and we record them separately. A Google model release does not by itself establish a change in either one.
| Date published | Release, in Google's words | Scope Google states |
|---|---|---|
| 21 July 2026 | "3.6 Flash: An upgraded model for your daily life" | Google's assistant app. |
| 13 August 2026 | "Introducing Gemini 3.7 Flash" | The post does not mention AI Overviews or AI Mode. |
| 2 September 2026 | "Introducing Gemini 3.8 Flash and 3.8 Flash Cyber" | Google AI Pro and Ultra subscribers in Google's assistant app, AI Mode in Google Search and Google Sheets. |
| 30 September 2026 | "Gemini 4 Argon: our next era of frontier intelligence" | The post does not mention AI Overviews or AI Mode. |
| 13 October 2026 | "Gemini 4 Argon: Built to solve your hardest problems" | Google AI Ultra and Pro subscribers in Google's assistant app and AI Mode in Search. |
| 15 October 2026 | "More ways to connect with the web from Search" | A product change, not a model release: AI Mode and AI Overviews get clearer inline links and more context about sources. |
| 28 October 2026 | "Gemini 4 Carbon: our next frontier model" | The post does not mention AI Overviews or AI Mode. |
How we mark a release on our time series
These are our annotation rules, in force from 9 November 2026. They apply to every chart and table that compares two captures.
- Provider-dated only. We mark a release only when the provider's own page dates it. A report, a screenshot or a leak is not marked.
- Every mark carries six fields: the provider, the release in the provider's words, the date the provider published, the source URL, the date we read it, and the scope the provider states.
- Three mark types. A model release names a new model. A default change says a model became the default for a plan. A product change alters an answer surface without naming a model, such as the Google post of 15 October 2026.
- Placement. A mark sits on the date the provider published. When the provider describes a rollout window, such as "this week", we record that window in words and do not guess an end date.
- Between captures. When a mark falls between two capture dates, the comparison carries a note naming the mark. We never attribute a change in a named count to a release. A change is reported only where the two 95 percent intervals separate, under our published method.
- Plans are not our setting. Our captures are signed-out, single-turn answers in US English. A release scoped to a paid plan does not tell us what a signed-out answer uses, so we record the stated scope and infer nothing further.
- Corrections. If a provider edits a release note, we keep our first reading with its date and add the new reading beside it.
Marks between our two Index captures
The Absence Index August release was captured on 28 August 2026 and the September release on 22 and 23 September 2026, as recorded on our data page. These provider-dated marks fall from 28 August to 23 September 2026:
| Date | Provider | Mark type | Release |
|---|---|---|---|
| 1 September 2026 | Anthropic | Model release | "Claude Fable 5.1 and Claude Mythos 5.1 launch" |
| 2 September 2026 | Model release | "Introducing Gemini 3.8 Flash and 3.8 Flash Cyber", scoped to paid subscribers in AI Mode | |
| 3 September 2026 | OpenAI | Model release | "Introducing GPT-6 Astra", limited organizations first |
| 21 September 2026 | Perplexity | Model release | "Effort Mode, GPT-6 Astra, and Skills Marketplace" |
| 22 September 2026 | OpenAI | Model release | "GPT-6 Sol and Luna in Work and Codex", outside the Chat tab |
| 22 September 2026 | Anthropic | Model release | "Claude Opus 5.5 launch", the first capture day |
The two releases also differ in design, and our data page compares standings across releases only where a study shows the test. The marks explain nothing on their own. They tell a reader which provider changes to check before reading a later comparison.
Sources
- OpenAI, ChatGPT release notes, entries dated 6 August to 26 October 2026 (read 9 November 2026).
- Anthropic, Claude release notes, entries dated 24 July to 7 October 2026, and the Anthropic newsroom (read 9 November 2026).
- Perplexity changelog, entries dated 27 July to 5 October 2026 (read 9 November 2026).
- Google, release notes for its assistant app, entry dated 21 July 2026, and Google blog posts dated 13 August to 28 October 2026, linked above (read 9 November 2026).
- Broadcastwell, Absence Index capture dates (read 9 November 2026).
Related: our note on engine divergence explains why each engine is read separately, our release notes list our own changes, how to cite our research gives the release DOIs, and the completed-case format shows where a release note appears in a client report.