ChatGPT — September 17, 2025

September 17, 2025

v2025-09-17-12816332 includes 3 new features and 0 fixes. What’s new

Source: official ChatGPT & Codex release notes. Summaries are written from the official notes; see how we work.

Added

What’s new
When you select GPT-5 with Thinking in ChatGPT, you’ll see a new thinking time toggle in the message composer.
Standard (new default, balancing speed and intelligence) and Extended (the previous default for Plus) are available to all Plus, Business users

Toggle thinking time in the message composer
We’re giving Plus, Business, and Pro users more control over how long GPT-5 thinks before responding. You can now choose the level of reasoning time, so you can decide whether you want a quicker answer or more in-depth reasoning for your task.
How it works
Pro users get two additional options: Light (snappiest) and Heavy (deeper reasoning).
All queries default to Standard unless you choose to change it. Once you choose a different thinking time, your preference is saved and used for future queries until you switch again.
Why we’re making this change
We’ve heard from some of you that GPT-5 Thinking’s answers can take longer than you’d like. Now you can decide what you need in the moment:
Light / Standard → quicker answers that still apply reasoning, balancing speed and intelligence.
Extended / Heavy → more time for deeper, more comprehensive responses when the stakes are higher or the question is more difficult.
What’s next
The thinking-time toggle is live today on chatgpt.com. Settings you choose on the web won’t yet sync to mobile, but we’ll bring this control to our iOS and Android apps in the coming weeks.

Get notified the minute the next ChatGPT & Codex release ships

AI Drops sends a push with a plain-English summary of every release.