OpenAI Models Updates & Release Notes

We’re updating GPT-5.5 Instant in ChatGPT and the API to improve response style and quality. It’s now easier to read, more natural in everyday conversations, and better paced in practical help tasks, with fewer overly long or bullet-heavy responses.

With this update, canvas will no longer be available in GPT-5.5 Instant or GPT-5.5 Thinking. Writing and coding functionality is now supported directly in chat responses through writing blocks and code blocks. Paid users can continue using canvas for a limited time through legacy models until those models are sunset.

GPT-5.4 mini rollout in ChatGPT

We’re rolling out GPT-5.4 mini in ChatGPT. GPT-5.4 mini is available to Free and Go users via the “Thinking” feature in the + menu. For all other users, GPT-5.4 mini is available as a rate limit fallback for GPT-5.4 Thinking.

For Plus, Pro, and other paid users, GPT-5.4 mini will be used as a fallback for GPT-5.4 Thinking when rate limits are reached, helping with continued access to reasoning capabilities during high usage. Enterprise customers will retain the option to default Auto routing to GPT-5.4 mini, if preferred.

GPT-5.4 mini will not appear as a selectable model in the model picker, and GPT-5 Thinking mini will be retired as a selectable option in 30 days. Learn more in our blog post.

GPT‑5.4 Release Notes

GPT‑5.4 brings together the best of our recent advances in reasoning, coding, and agentic workflows into a single frontier model. It incorporates the industry-leading coding capabilities of
GPT‑5.3‑Codex⁠
while improving how the model works across tools, software environments, and professional tasks involving spreadsheets, presentations, and documents. The result is a model that gets complex real work done accurately, effectively, and efficiently—delivering what you asked for with less back and forth.

In ChatGPT, GPT‑5.4 Thinking can now provide an upfront plan of its thinking, so you can adjust course mid-response while it’s working, and arrive at a final output that’s more closely aligned with what you need without additional turns. GPT‑5.4 Thinking improves deep web research, particularly for highly specific queries, while better maintaining context for questions that require longer thinking. GPT‑5.4 Thinking also has improved context window management that supports its ability to think for longer. Together, these improvements mean higher-quality answers that arrive faster and stay relevant to the task at hand.

GPT‑5.3 Instant

GPT‑5.3 Instant delivers more accurate answers, richer and better-contextualized results when searching the web, and reduces unnecessary dead ends, caveats, and overly declarative phrasing that can interrupt the flow of conversation.

This update focuses on the parts of the ChatGPT experience people feel every day: tone, relevance, and conversational flow. These are nuanced problems that don’t always show up in benchmarks, but shape whether ChatGPT feels helpful or frustrating. GPT‑5.3 Instant directly reflects user feedback in these areas.

Jan 10, 2026

We lowered the Standard and Light thinking time as we observed users prefer faster responses. As part of this update, the Extended thinking setting for GPT-5.2 was unintentionally changed to be lower which we have now fixed.

February 3, 2026

We made another small reduction to Standard thinking time based on testing.

February 4, 2026

We’re restoring the Extended thinking level for GPT-5.2 Thinking to its prior setting, correcting the inadvertent reduction from January. Extended is now back to its prior level.

We periodically adjust the default thinking time for our reasoning models. These changes are based on ongoing experiments to find the best balance between answer quality and response speed for users.

The thinking level toggle introduced in September 2025 gives users more choice beyond Standard, allowing them to select the right thinking level for their question—whether they want lighter, faster responses or more extended reasoning when depth and accuracy matter more.

Thinking time is not directly comparable across different models. Each model is tuned independently to what works best for users. We’ll continue to adjust these settings as models evolve, and will keep giving users clear controls when there are meaningful tradeoffs to choose from.

Under-18 (U18) Principles

ChatGPT’s new Under-18 (U18) Principles builds on the existing safety rules that apply to all users, adding age-appropriate guidance where appropriate for the developmental needs of teens, aged 13-17. This update clarifies how those rules are intended to apply in teen conversations, recognizing that teens benefit from clearer boundaries, reduced exposure to potentially harmful content and stronger real-world support when risks arise. The assistant should meet teens where they are, engaging with them in a respectful and transparent manner, while refusing to participate in self-harm, sexualized or violent immersive roleplay, dangerous activities, substance misuse or any efforts to conceal harm. When credible risks arise, the model should prioritize prevention and early interventions, offer safer alternatives and encourage involvement of parents, guardians and other trusted adults or professionals – making clear that AI can provide guidance and information, but cannot replace real-world care.

Other updates

This release also includes minor edits and clarifications for consistency and readability throughout the document.

More information can be found in this blog post, and the latest version of the Model Spec is available at model-spec.openai.com.