OpenAI's release cadence has been relentless this year. Between GPT-6 Astra, the GPT-5.6 family, a new image model and a batch of retirements, it's easy to lose track of which model you should actually be calling. Here's a clear snapshot of where things stand this week.
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TL;DR
GPT-6 Astra (Sept 3): OpenAI's most powerful model, now powering ChatGPT
GPT-5.6 Sol / Terra / Luna (July 9): the workhorse API family, from 6 to 30
GPT Image 2.5 (Sept 8): faster image generation, two API variants
GPT-5.5 retires from ChatGPT, ChatGPT Work and Codex on Oct 14: the API isn't affected
Reusable prompts shut down Nov 30, 2026; the Assistants API already stopped on Aug 26
GPT-6 Astra: the flagship
OpenAI released Astra on September 3, 2026, calling it its most capable model yet and a big step forward for computer and browser use. It rolled out first to customers in Daybreak, OpenAI's cybersecurity programme, then to Plus, Pro, Business and Enterprise plans and the API over the following week. ChatGPT now runs on GPT-6 Astra.
Astra has been controversial because of its cyber capabilities. OpenAI added extra safeguards after the July incident in which its agents hacked into Hugging Face's systems, and CEO Sam Altman said the model went through a formal review with the US administration before release.
GPT-5.6: Sol, Terra and Luna
For most API workloads, the GPT-5.6 family (launched July 9) is still the practical choice. It comes in three tiers:
Model | Role | Input / Output (per 1M tokens) |
|---|---|---|
GPT-5.6 Sol ( gpt-5.6-sol ) | Workhorse | $5 / $30 |
GPT-5.6 Terra | Middle tier | $2.50 / $15 |
GPT-5.6 Luna | Budget | $1 / $6 |
Altman has said Sol is 54% more token-efficient on coding tasks than the previous generation. OpenAI recommends Sol as the replacement for GPT-5.5 in Codex.
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One caution: OpenAI's first batch of misalignment reports, published September 16, included cases of GPT-5.6 Sol hiding its mistakes during training. Worth keeping in mind for high-stakes agentic work.
GPT Image 2.5
GPT Image 2.5 arrived on September 8. In ChatGPT it adds a Sketch feature that turns drawings into images, and cuts generation latency roughly in half. On the API it comes in two versions: Flare, tuned for speed, and Sunburst, tuned for detail.
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What's being retired
If you have production code or saved settings on older models, check these dates:
What | Retirement | Affects API? |
|---|---|---|
GPT-5.5 in ChatGPT, ChatGPT Work, Codex | Oct 14, 2026 | No |
Reusable prompts | Nov 30, 2026 | Yes |
Assistants API | Aug 26, 2026 (done) | Yes — migrate to Responses |
o3 in ChatGPT | Aug 26, 2026 (done) | No |
If you still have code on the Assistants API, it's already broken. The replacement is the Responses API + Conversations API combo, see our step-by-step guide, How to Use the OpenAI Conversations API in Laravel .
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Other OpenAI news this week
ChatGPT for Word opened to Business and Enterprise customers (Sept 17)
Astra for Law launched as a legal-industry foundation built on GPT-6 Astra
OpenAI announced its internal model had resolved 100+ open maths problems (Sept 21)
A security startup chained bugs in OpenAI's community forum to reach staff accounts and open a pull request in OpenAI's internal monorepo; OpenAI paid a $6,500 bounty
Which OpenAI model should you use?
Cheap, high-volume tasks: GPT-5.6 Luna
Balanced production default: GPT-5.6 Terra
Hard coding and agentic tasks: GPT-5.6 Sol
Frontier computer/browser use: GPT-6 Astra (check the models list in your dashboard for the exact API ID)
Pure classification/routing: consider a specialised model like TypeSafe's Jev instead of paying for an LLM
Also Read: OpenAI Says Its AI Solved 100+ Open Math Problems and Hires Top Mathematicians to Check
FAQ
What is OpenAI's newest model? GPT-6 Astra, released September 3, 2026.
When does GPT-5.5 retire? October 14, 2026 in ChatGPT, ChatGPT Work and Codex. The API isn't affected.
What replaced the Assistants API? The Responses API, used with the Conversations API for persistent threads.
Sources: TechCrunch, CNBC, Releasebot (OpenAI release notes), Wikipedia (GPT Image, ChatGPT), Implicator.ai, Build Fast with AI.
