OpenAI Model Release Timeline: GPT-5 to GPT-6, With Real Dates

OpenAI shipped GPT-5 on 7 August 2025 and GPT-6 Cyber on 5 November 2026, with a long list of releases between them, according to OpenAI's own API changelog. The longest gap between headline models was 98 days (GPT-5 to GPT-5.1). The shortest was 26 days (GPT-6 Astra to GPT-6.1 Sol). Below is the full dated list, the one government-requested delay, and what the cadence means for planning.

Key Takeaways

• The dates below come from OpenAI's API changelog, which I read for August 2025 to November 2026. API availability dates can differ from ChatGPT rollout dates by a day or more.
• Headline text models arrived every 26 to 98 days (my arithmetic from changelog dates): GPT-5, 5.1, 5.2, 5.4, 5.5, 5.6, then GPT-6 Astra.
• GPT-5.6 is the only release I found where a government request changed the schedule: a limited preview on 26 June 2026, then general availability on 9 July.
• Prices fell sharply inside the GPT-5.6 family before GPT-6 arrived. Luna was cut 80% and Terra 20% on 30 July 2026, per the changelog.
• GPT-6 split the line into tiers that update separately: GPT-6.1 Sol came a week after GPT-6 Sol, and GPT-6.1 Terra a month later, while Astra and Luna have not been refreshed.
• Do not build on a model name without a migration plan. Most tiers above were replaced within about three months.

The full timeline

All dates are API release dates from the OpenAI changelog unless another source is named.

2025: GPT-5 to GPT-5.2

2026, first half: GPT-5.2 to GPT-5.5

2026, second half: GPT-5.6 to GPT-6.x

I left out audio, realtime and image snapshots unless they were headline releases. The changelog lists many more. One date conflict worth flagging: search summaries I ran gave 3, 4 or 5 September for Astra's first access. The changelog and 9to5Mac both date the release to 3 September, with wider ChatGPT access following over the next day or so, and I use that.

The GPT-5.6 staggered rollout

GPT-5.6 is the one release where the schedule bent to government input. What I could verify:

• 26 June 2026: GovInfoSecurity reported that the Trump administration asked OpenAI to limit the release and requested access to the model and the list of users. OpenAI called the first release "a limited preview for a small group of trusted partners" and said it intended general availability "in the next few weeks".
• Context: The same report notes a 5 June executive order creating a voluntary 30-day government review period for frontier models, and earlier export controls on Anthropic's Fable 5 model.
• 9 July 2026: TestingCatalog dates the release of all three tiers to 9 July, and the changelog agrees. That is 13 days after the preview.

What I could not verify: the number of approved companies in the preview (GovInfoSecurity did not state it), and several details of who inside government asked for what. Those came from secondary reports and I left them out. OpenAI also opened Astra in stages, which 9to5Mac noted mirrored the GPT-5.6 release.

GPT-5.6 pricing at launch

On 9 July the API prices were $5/$30 (Sol), $2.50/$15 (Terra) and $1/$6 (Luna) per million tokens, per TestingCatalog. Luna and Terra were cut on 30 July and Sol on 21 August. As of November 2026, OpenAI's pricing page lists GPT-5.6 Sol at $4/$20, Terra at $2/$12, Luna at $0.20/$1.20.

Sources conflict on how long the Sol promotional price lasts. The changelog says "through at least" 21 November 2026, while the pricing page says 30 November. I trust the pricing page because it is the more recent document, but check it before you budget.

What the cadence tells you

The average is about 60 days, but the range is wide, so "a new model every two months" is a rough guide, not a schedule. Since GPT-6, updates are per tier, so the family never has a single "latest" version.

What this means for marketers and founders

• Pin model IDs, and put a review date on each. If a workflow says "uses GPT", it will drift. I keep a one-line record per automation: model ID, date tested, test set used. My model evaluation protocol shows the format.
• Budget for price swings in both directions. Luna fell 80% in one change, but Sol's GPT-5.6 price carried a promotional end date. Check expiry dates, not only current rates.
• Do not chase every release. My own rule of thumb is to re-test only when a release changes price by about half or adds a capability my workflow lacks. The release-fatigue framework explains the logic.
• Treat staged access as normal. If a model you want is "limited preview", plan on the previous version for at least two weeks. GPT-5.6 took 13 days from preview to general availability.
• Route by task, not by brand. My model routing strategy shows how to swap tiers without rewriting workflows.

For the current tier-by-tier breakdown, read the GPT-6 family explained.

Caveats

• The changelog is OpenAI's own record. It does not list prices for most 2025 and early 2026 releases, so I did not state them.
• ChatGPT consumer rollouts often differ from API dates. I did not map those.
• I did not find an API changelog entry for a "GPT-5.3" general model beyond Codex and chat-latest variants, so I list only what is there.
• The 12 May Daybreak announcement and 26 June preview come from news coverage, not the changelog.

FAQ

When was GPT-5 released?

GPT-5, GPT-5 mini and GPT-5 nano appeared in the OpenAI API on 7 August 2025, according to the API changelog. GPT-5.1 followed on 13 November 2025, 98 days later.

When was GPT-5.6 released?

OpenAI released the GPT-5.6 family (Sol, Terra and Luna) on 9 July 2026. A limited preview for trusted partners began on 26 June 2026, after the US administration asked OpenAI to limit the initial release, per GovInfoSecurity.

When was GPT-6 released?

GPT-6 Astra was released on 3 September 2026. GPT-6 Sol and Luna followed on 22 September, GPT-6.1 Sol on 29 September, GPT-6.1 Terra on 26 October, and GPT-6 Cyber on 5 November.

Why was the GPT-5.6 release staggered?

GovInfoSecurity reported that the administration asked OpenAI to limit the release and share the user list. Other reports in my search results cite security concerns, but I did not open them, and OpenAI has not published its reasoning in anything I read.

How often does OpenAI release a new model?

Headline text models have come every 26 to 98 days since August 2025, by my calculation from changelog dates. Smaller releases such as Codex, audio and image models arrive between them.

Which OpenAI model is newest today?

As of this writing in November 2026, the newest in the changelog I read is GPT-6 Cyber (5 November), but it is restricted. The newest generally available text model is GPT-6.1 Terra (26 October).

Did GPT-5.6 prices change after launch?

Yes. On 30 July 2026 Luna was cut 80% and Terra 20%, and on 21 August Sol was cut to $4 input and $20 output per million tokens, per the changelog.

Want help with this?

I'm Younus Fardeen, an organic growth, SEO and AEO strategist with 4+ years of marketing experience across edtech and startup teams. If you want help building an AI-assisted content workflow that survives model changes, see my work and reach me through the contact form at younusfardeen.com.