# AI updates, September–October 2026: models, prices, shutdowns

URL: https://infro.io/blog/ai-updates-september-october-2026
Author: INFRO Editorial (https://infro.io/blog/editorial)
Publisher: INFRO
Published: 2026-10-06
Last modified: 2026-10-06
Last reviewed: 2026-10-06 (next review due 2026-11-05)
Topic: Evaluation and models
Format: Analysis

> Between 1 September and 6 October 2026 OpenAI shipped GPT-6 Astra, Sol and Luna and GPT-6.1 Sol; Anthropic shipped Claude Fable 5.1, Opus 5.5 and Sonnet 5.5; Google made Gemini 3.8 Flash generally available; xAI, DeepSeek and TypeSafe released Grok 4.7, V4.1-Flash and Jev. For production teams the operational changes matter as much: forced tool use now fails on new Claude models, GPT-6 Astra needs the Responses API for tools, Sora 2 and Sonar Chat Completions ended, OpenAI retires a long list of snapshots on 23 October, and Gemini Flash prices double on 1 January 2027.

The five weeks from 1 September to 6 October 2026 were one of the busiest stretches of the year for anyone running AI in production. OpenAI, Anthropic and Google each shipped new top models; xAI, DeepSeek and Alibaba updated theirs; and TypeSafe released a model that does not generate text at all. The same weeks ended two widely used APIs, scheduled a long list of shutdowns, and put dates on price rises.

This roundup sticks to what each vendor published on its own pages, read on 6 October. It leaves out benchmark claims and concentrates on what changes a budget, a deployment or a line of code.

[Diagram: Releases and shutdowns from each vendor's changelog or release notes, 1 September to 6 October 2026.]

## OpenAI: GPT-6 in three tiers, then GPT-6.1 Sol

OpenAI released **GPT-6 Astra** on 3 September as its most capable model, at $10 per million input tokens and $50 per million output[1][2]. Requests with more than 272K input tokens are billed at twice the input rate and 1.5 times the output rate for the whole request[2]. Astra arrived with constraints that matter to existing code: it does not accept `none` reasoning effort, custom `temperature` or `top_p`, or `logprobs`, and tool calling requires the Responses API[1]. AWS made Astra generally available on Amazon Bedrock on 8 September[3].

On 22 September OpenAI added **GPT-6 Sol** at $2 input, $0.20 cached input and $10 output, and **GPT-6 Luna** at $0.10, $0.01 and $0.50[1]. A week later, on 29 September, **GPT-6.1 Sol** followed at the same $2 and $10, with cached input at $0.10, alongside an "ultrafast" service tier for Astra on the Responses API[1].

The platform changed around the models too. The Agents API entered public beta on 10 September; project API keys can now carry expiry dates with an admin-enforced maximum lifetime; and organizations and projects gained controls over who may create keys[1]. Sora 2 and the Videos API shut down on 24 September[4].

## Anthropic: Fable 5.1, Opus 5.5 and Sonnet 5.5

Anthropic launched **Claude Fable 5.1** on 1 September at $10 and $50, with cache reads cut to $0.25 per million, a 1M-token context and 128K output[5]. **Claude Opus 5.5** followed on 22 September at $4 and $20, below Opus 5's $5 and $25, and **Claude Sonnet 5.5** on 28 September at $2 and $10, which the launch note calls introductory pricing[5][6]. Anthropic also confirmed that Sonnet 5's $2 and $10 is now its standard price and that a planned increase to $3 and $15 will not happen[6].

The launches carry breaking changes that a model-id swap will hit:

- On Fable 5.1, Opus 5.5 and Sonnet 5.5, forced tool use — `tool_choice` of `any` or `tool` — returns a 400 error; Anthropic's advice is `auto` with strict tool use[5].
- On Opus 5.5, thinking cannot be disabled; both `disabled` and `enabled` thinking settings return a 400[5].
- On Sonnet 5.5, turning off up-front thinking now means `thinking: {"type": "between_tools"}` instead of `disabled`, and thinking blocks are tied to the model and the conversation[5].

Anthropic also made cache diagnostics generally available on 23 September, and resumed billing on 24 September for refusals that arrive before any output in three categories[5]. On 30 September it announced the retirement of Claude Sonnet 4.5 on 30 November 2026, with Sonnet 5.5 as the replacement[5]. Claude Haiku 4.5 is listed for retirement no sooner than 15 October 2026[7].

## Google: Gemini 3.8 Flash and a dated price rise

Google made **Gemini 3.8 Flash** generally available with a 1M-token context and 64K output[8]. It prices 3.8, 3.7 and 3.6 Flash identically: $0.75 input and $3.75 output through 31 December 2026, then $1.50 and $7.50 from 1 January 2027, with context caching doubling on the same day[9]. Any forecast that runs past December should use the 2027 rate.

Migration is not a model-id swap here either. Google's notes say to remove the `temperature`, `top_p` and `top_k` sampling parameters, to replace `thinking_budget` with the `thinking_level` setting (low, medium by default, or high), and that the `minimal` level returns an error on 3.8 Flash[8]. Google lists 2 October as the shutdown date of the original Nano Banana image model, `gemini-2.5-flash-image`, and 22 October as the earliest shutdown of the Veo 3.1 preview ids[10][9].

## xAI, DeepSeek, Alibaba and Mistral

**xAI** released **Grok 4.7** in September[11]: $2 input, $0.50 cached and $6 output below 200K prompt tokens, $4 and $12 above, with a 500K-token context and reasoning effort from `low` to `xhigh`[12].

**DeepSeek** released **V4.1-Flash** on 10 September, served under the `deepseek-flash` name, with new rates and off-peak prices at half the peak rate; the older `deepseek-v4-flash` names now route to it[13]. Its pages disagree about V4 Pro: the announcement says V4 Pro requests move to V4.1-Flash from 14 September until V4.1-Pro launches[13], while the change log says DeepSeek will keep serving V4 Pro after that date with billing unchanged[14]. Check which model your responses report.

**Alibaba** moved the unpinned `qwen3.8-max` alias to the new `qwen3.8-max-0902` snapshot on 5 September, with pricing unchanged[15]. A request that named the alias got a different model with no code change — the case for pinning snapshots in production.

**Mistral** gave one day's notice on 29 September that OCR 4.0 would retire on 30 September, recommending OCR 4.1 at the same price, and set 31 October for retiring GLM 5.2 on its platform in favour of GLM 5.3[16].

## Perplexity ends Sonar Chat Completions

Perplexity ended Sonar Chat Completions support on 27 September. Synchronous and streaming requests keep working because Perplexity is reformulating them as Agent API requests, rolling out by model; asynchronous Sonar requests are no longer supported and have to move to the Agent API's background mode[17]. A request that keeps working while its semantics change underneath it is worth re-testing, not just leaving alone.

## TypeSafe Jev: a model that does not write

TypeSafe announced Jev on 15 September as its first "System One" model: it answers typed questions about content — yes/no, one of a set of options, a score on a rubric — with probabilities rather than text, and bills $0.042 per million input tokens with output free[18]. It is a different kind of model from everything else in this list, built for the classification, routing and checking work that otherwise runs on chat models. [What Jev is](https://infro.io/blog/what-is-jev-typesafe), [its use cases](https://infro.io/blog/jev-use-cases) and [the cost arithmetic](https://infro.io/blog/jev-cost-per-decision) cover it in depth.

## What the month says about running AI in production

[Diagram: List rates of the models released or repriced in the period, from each vendor's pricing or model page, read 2026-10-06.]

**Upgrades are code changes.** Every major vendor shipped a new version that rejects parameters the previous one accepted: sampling parameters on GPT-6 Astra and Gemini 3.8 Flash, disabled thinking and forced tool use on the new Claude models[1][5][8]. A model id in a configuration file is not a safe place to change models without a test run.

[Diagram: Changes in request handling that arrived with version upgrades, from each vendor's release notes, read 2026-10-06.]

**Prices fell at the top and the bottom, with dates attached.** Opus 5.5 lists below Opus 5, and GPT-6 Luna lists at $0.10 input[6][1]. But Gemini Flash's rate doubles in January and Sonnet 5.5 launched at introductory pricing[9][5]. Budget on the rate that will apply when the money is spent, not the one on the launch post.

**Notice periods are shrinking at the edges.** Most retirements came with months of notice, but Mistral's OCR 4.0 had one day, and aliases such as `qwen3.8-max` moved on their own[16][15]. Teams that learn about a retirement from failing requests find out on the vendor's schedule, not their own.

**APIs are diverging.** Tool calling on GPT-6 Astra needs the Responses API, and Perplexity's Sonar now runs as Agent API calls[1][17]. The OpenAI-compatible Chat Completions shape remains the common denominator, but it no longer reaches every feature of every top model.

## Deadlines for the next two quarters

[Diagram: Dated shutdowns and price changes from each vendor's deprecation and pricing pages, read 2026-10-06. "Earliest" dates are the vendor's own wording.]

The largest single event is OpenAI's 23 October shutdown of older snapshots, among them `gpt-3.5-turbo-0125`, `gpt-4-turbo`, `gpt-4.1-nano`, `gpt-4o-2024-05-13`, the dated o1, o3-mini and o4-mini snapshots, and `gpt-image-1`[4]. On 30 November OpenAI also shuts down the reusable prompts API, Agent Builder and the Evals platform, and on 1 December `gpt-image-1.5` and `gpt-image-1-mini`[4]. OpenAI deprecated GPT-5.4 nano, GPT-5.1 and GPT-5.3-Codex on 1 October, with shutdown on 1 April 2027[4].

Regulation has dates too. The European Commission states that the AI Act's rules for high-risk systems in areas such as employment, education and critical infrastructure apply from 2 December 2027[19]. Teams using AI to screen candidates or score applicants should be designing for that now.

[Diagram: Four steps that cover most of the changes above.]

## Handling a month like this with INFRO

INFRO's [model catalog](https://infro.io/providers) carries each vendor's list rate for the models above as reference data for cost estimation, with a page per model, such as [GPT-6 Luna](https://infro.io/models/openai/gpt-6-luna) and [Claude Sonnet 5.5](https://infro.io/models/anthropic/claude-sonnet-5.5). Each provider still bills its own account directly; a negotiated rate entered for your organization replaces the list rate in every estimate.

Three gateway features map onto the checklist. **Usage grouped by model** shows whether any traffic still uses a retiring id, and how much: `GET /v1/usage?group_by=model` returns requests and estimated cost per model across every application that calls through the gateway. **Routes** turn a model change into a configuration change: a weighted route can send 5% of traffic to the replacement, and the old model stays as a fallback target until it is removed, as the [deprecation playbook](https://infro.io/blog/model-deprecation-migration-playbook) describes. **Model allowlists** stop applications from adopting a model the organization has not evaluated, whatever was announced this week.

## Sources

1. Changelog — OpenAI. https://developers.openai.com/api/docs/changelog (accessed 2026-10-06)
2. Pricing — OpenAI. https://developers.openai.com/api/docs/pricing (accessed 2026-10-06)
3. OpenAI GPT-6 Astra is now generally available on Amazon Bedrock — AWS. https://aws.amazon.com/about-aws/whats-new/2026/09/openai-gpt-6-astra-on-amazon-bedrock/ (accessed 2026-10-06)
4. Deprecations — OpenAI. https://developers.openai.com/api/docs/deprecations (accessed 2026-10-06)
5. API release notes — Anthropic. https://platform.claude.com/docs/en/release-notes/api (accessed 2026-10-06)
6. Pricing — Anthropic. https://platform.claude.com/docs/en/about-claude/pricing (accessed 2026-10-06)
7. Model deprecations — Anthropic. https://platform.claude.com/docs/en/about-claude/model-deprecations (accessed 2026-10-06)
8. What's new in Gemini 3.8 Flash — Google. https://ai.google.dev/gemini-api/docs/latest-model (accessed 2026-10-06)
9. Gemini Developer API pricing — Google. https://ai.google.dev/gemini-api/docs/pricing (accessed 2026-10-06)
10. Gemini deprecations — Google. https://ai.google.dev/gemini-api/docs/deprecations (accessed 2026-10-06)
11. Introducing Grok 4.7 — xAI. https://x.ai/news/grok-4-7 (accessed 2026-10-06)
12. grok-4.7 — xAI. https://docs.x.ai/docs/models/grok-4.7 (accessed 2026-10-06)
13. DeepSeek-V4.1-Flash: Smarter, Faster, More Efficient — DeepSeek. https://api-docs.deepseek.com/news/news260910/ (accessed 2026-10-06)
14. Change Log — DeepSeek. https://api-docs.deepseek.com/updates (accessed 2026-10-06)
15. Update Notice for Qwen3.8-Max Models — Alibaba Cloud. https://www.alibabacloud.com/en/notice/model_studio_update_notice_for_qwen38max_models_863 (accessed 2026-10-06)
16. Changelog — Mistral AI. https://docs.mistral.ai/getting-started/changelog (accessed 2026-10-06)
17. Migrate from Sonar to the Agent API — Perplexity. https://docs.perplexity.ai/docs/agent-api/migrate-from-sonar/overview (accessed 2026-10-06)
18. Introducing System One Models & Jev — TypeSafe. https://typesafe.ai/blog/introducing-system-one-models-and-jev (accessed 2026-10-06)
19. AI Act — European Commission. https://digital-strategy.ec.europa.eu/en/policies/regulatory-framework-ai (accessed 2026-10-06)