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TL;DR
OpenAI has scheduled API model shutdowns for Dec. 11, 2026, and Jan. 14, 2027, with some older models already removed on Oct. 23. Listed replacement prices vary sharply: several GPT-4 family users could pay less per token, while GPT-5 mini and nano users face higher rates, before accounting for reasoning tokens and migration work.
OpenAI is retiring API models in stages, with shutdowns scheduled for Dec. 11, 2026, and Jan. 14, 2027, and some older model IDs already unavailable since Oct. 23. The listed replacements have substantially different token prices, so the cost of migrating depends on a company’s current model, usage mix and the extra output generated by reasoning models.
OpenAI’s deprecations page, checked by ThorstenMeyerAI.com on Nov. 1, 2026, lists GPT-5, GPT-5 mini, GPT-5 nano, GPT-5 pro, o3 and o3-pro for retirement on Dec. 11. The listed replacements are from the GPT-5.6 family. On Jan. 14, GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini snapshots are scheduled to leave the API, with GPT-6 Luna named as the replacement.
Some older IDs, including GPT-3.5 Turbo, GPT-4 Turbo, the original GPT-4o snapshot, o1 and o4-mini, were scheduled to shut down on Oct. 23. The source says calls using those IDs may already fail. OpenAI says fine-tuned versions follow the shutdown schedule of their base models; the replacements listed in the source do not support fine-tuning.
Prices quoted in the source are standard rates per million tokens for short contexts, up to 272,000 tokens, and were checked Nov. 1. GPT-4o is listed at $2.50 per million input tokens and $10 per million output tokens, compared with $0.10 and $0.50 for GPT-6 Luna. But the economics go the other way for some GPT-5 users: GPT-5 nano’s listed replacement costs $0.20 input and $1.20 output, versus $0.05 and $0.40; GPT-5 mini’s replacement is $2 input and $12 output, versus $0.25 and $2. Those are token-price comparisons, not a full estimate of migration costs.
Infographic 01 · The shutdown calendar
What stops working, and when
OpenAI's API deprecations, as listed on 1 November 2026. GPT-4o and GPT-4.1 already left ChatGPT on 13 February 2026; this round is about apps built on the API.
- 23 Oct 2026Already offAlready shut down
gpt-3.5-turbo,gpt-4,gpt-4-turbo,gpt-4.1-nano,gpt-4o-2024-05-13,o1,o1-pro,o3-mini,o4-mini,gpt-image-1. Calls to these fail today. - 30 Nov 2026Your testsEvals platform, Agent Builder, reusable prompts
Not models, but tools many teams test with. Existing evals became read-only on 31 Oct. Export them first.
- 11 Dec 2026Notified 11 JunGPT-5 family and o3
gpt-5→gpt-5.6-sol·gpt-5-mini→gpt-5.6-terra·gpt-5-nano→gpt-5.6-luna·o3→gpt-5.6-sol·gpt-5-pro,o3-pro→gpt-5.6-sol(pro mode) - 14 Jan 2027Notified 14 OctGPT-4o, GPT-4o mini, GPT-4.1, GPT-4.1 mini
Snapshots
gpt-4o-2024-08-06,gpt-4o-2024-11-20,gpt-4o-mini-2024-07-18,gpt-4.1-2025-04-14,gpt-4.1-mini-2025-04-14→gpt-6-luna. Fine-tuned versions follow their base model. - Jan to Apr 2027Plan aheadAudio, speech, older GPT-5.x
6 Jan:
tts-1and others · 20 Jan: older audio and realtime models · 26 Feb:whisper-1, GPT-4o transcription · 1 Apr:gpt-5.1,gpt-5.4-nano,gpt-5.3-codex
Sources: OpenAI deprecations page (checked 1 Nov 2026) · OpenAI Help Center, model release notes. Dates as listed by OpenAI; shutdowns can be rescheduled.
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How Model Changes Affect API Bills
The price table shows why companies cannot estimate migration costs from a single headline rate. An application moving from GPT-4o to GPT-6 Luna could see lower listed per-token prices, while one moving from GPT-5 mini or nano could face higher rates. Actual bills depend on input and output volume, cached tokens, prompt length and model behavior.
There may also be engineering and testing costs beyond API charges. The source says the replacements are reasoning models: hidden reasoning tokens are billed as output, and some sampling parameters need to be removed. It also warns that a restrictive output limit can result in an empty answer that is still billed. Teams should compare real workloads, not just published rates, and test whether the replacement follows the application’s required output format and instructions.
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The Shutdown Dates and Model Spec
The schedule is part of a wider set of changes reported by ThorstenMeyerAI.com. OpenAI’s notice lists the API dates separately from its earlier ChatGPT changes: GPT-4o, GPT-4.1 and GPT-4.1 mini were removed from ChatGPT on Feb. 13, 2026, while the current round concerns products and services built on the API.
The source also reports that OpenAI revised its Model Spec on Oct. 29, 2026, removing much of its detailed style guidance, including a default to format answers in Markdown. That change does not itself set API prices or shutdown dates, but it adds a behavior-testing concern for applications that rely on consistent formatting. The source quotes OpenAI as saying its models “do not yet fully reflect” the Spec.
OpenAI’s page says generally available models receive at least six months’ notice unless safety or compliance concerns require a faster schedule. The Jan. 14 shutdown notice was dated Oct. 14, three months beforehand; the source notes that the entry does not explain how that timing relates to the stated notice policy.
Costs Beyond Published Token Rates
The source provides token prices, not a complete migration budget. It does not quantify engineering time, evaluation expenses, changes in token use after migration or the cost of correcting application behavior. Pricing may also change; the figures are a snapshot checked on Nov. 1, 2026, and apply to short contexts up to 272,000 tokens.
It remains unclear why the January notice period is shorter than the six months OpenAI says it generally provides, and whether the company considers an exception applicable. The source says customers with contracts or committed spend should ask their OpenAI account teams. OpenAI also says some customers may be able to buy dedicated capacity to retain access after a shutdown, but availability and terms are not specified.
Teams should confirm whether their exact model IDs are affected. The schedule names dated snapshots, while short model names may appear in configurations, tests or automation tools. The source advises treating the short GPT-4o and GPT-4.1 names as covered by the January date, but customers should check OpenAI’s current deprecations page and their own account notices.
Audit IDs and Test Replacements
For teams with affected applications, the immediate step is to search code, configuration files, test fixtures and no-code workflows for model IDs, then compare the results against OpenAI’s current deprecation list. The Oct. 23 removals require attention now; teams using models scheduled for Dec. 11 or Jan. 14 have those dates as migration deadlines.
Before switching production traffic, developers can test representative prompts against the listed replacement, check output quality and formatting, and measure input and output token use. They should also review settings that may not be supported by reasoning models and set output limits that do not truncate responses. OpenAI’s deprecation page is the source for schedule updates; the source report says OpenAI emails affected customers. Any organization with contractual commitments or a need for continued access should ask its account team about notice, dedicated capacity and the applicable terms.
Key Questions
When are the main API model shutdowns?
The source lists Dec. 11, 2026, for GPT-5 family models and o3 variants, and Jan. 14, 2027, for specified GPT-4o and GPT-4.1 snapshots. Some older IDs were scheduled to shut down on Oct. 23, 2026.
Will migrating from GPT-4o lower my API bill?
At the listed short-context rates checked Nov. 1, GPT-6 Luna costs less per million input and output tokens than GPT-4o. That comparison does not establish total savings: usage, reasoning output, application changes and other costs can affect the bill.
Which users face higher listed replacement prices?
The source’s comparison shows higher per-token rates for GPT-5 nano users moving to GPT-5.6 Luna and GPT-5 mini users moving to GPT-5.6 Terra. The reported rates are $0.05 input and $0.40 output for GPT-5 nano versus $0.20 and $1.20 for its replacement, and $0.25 and $2 for GPT-5 mini versus $2 and $12 for its replacement, per million tokens.
Do the listed replacement models support fine-tuning?
According to the source, the listed replacements do not support fine-tuning, and OpenAI says fine-tuned models follow the shutdown schedule of their base models. Customers relying on fine-tuned versions should verify their options with OpenAI.
What should developers test before migrating?
Check model IDs, output quality, required formats, token usage and API settings. The source says reasoning models bill hidden reasoning tokens as output and may not support some sampling parameters; restrictive output limits may also lead to empty, billed answers.
Source: ThorstenMeyerAI.com
