GoKawiilOpenAI says it's rolling out a new update that improves the existing GPT-5.5 Instant model and retires multiple legacy models, including o3.
GPT-5.5 Instant was released on April 23, and it has made significant progress over the past few weeks, particularly in May 2026.
Now, in an updated document, OpenAI quietly confirmed that it has improved the quality of GPT-5.5, which means it'll now respond more accurately and use a better style for its answers.
OpenAI is also reducing long and bullet-heavy responses in an attempt to make GPT sound more human.
These changes mean GPT responses will now be easier to read and more natural in everyday conversation.
OpenAI says GPT-5.5 will be better paced in practical help tasks after this week's update.
OpenAI retires legacy models
While OpenAI is rolling out some nice upgrades, it's also sunsetting older legacy models to better serve its newer and most capable models.
On August 26, o3 will be retired from ChatGPT, but you'll be given a 90-day sunset period. GPT-4.5 will be retired from ChatGPT on June 27 following a 30-day sunset period.
How to select legacy model in ChatGPT Plus or Pro
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