OpenAI releases GPT-5.5 Instant, a new default model for ChatGPT
Source: TechCrunch
OpenAI announced on Tuesday the release of GPT‑5.5 Instant, the new default foundation model for ChatGPT, succeeding GPT‑5.3 Instant. The company says the model reduces hallucinations in sensitive domains such as law, medicine, and finance while preserving the low latency of its predecessor.
New Model Release
OpenAI released the latest GPT‑5.5 model last month, highlighting improvements in coding and knowledge‑work tasks. GPT‑5.5 Instant will be the default model for ChatGPT users, with the previous version remaining available for a limited time.
Performance Benchmarks
- AIME 2025 math test: GPT‑5.5 Instant scored 81.2, compared with 65.4 for GPT‑5.3 Instant.
- MMMU‑Pro multimodal reasoning benchmark: GPT‑5.5 Instant achieved 76, versus 69.2 for its predecessor.
Context Management and Memory Sources
The update places a strong emphasis on context handling:
- GPT‑5.5 Instant can use its search tool to reference past conversations, files, and Gmail, delivering more personalized answers.
- This feature is initially available to Plus and Pro users on the web, with a mobile rollout planned soon. OpenAI intends to extend it to Free, Go Business, and Enterprise users in the coming weeks.
- ChatGPT will now display memory sources across all models, allowing users to see where answers originated, delete outdated sources, or correct them if inaccurate.
- When a chat is shared, recipients will not see the underlying memory sources.
Developer Access
Developers can access the new model via the API using the identifier chat-latest. The older GPT‑5.3 model will remain available as an option for paid users for only three months.
Previous Model Withdrawal Controversy
OpenAI’s history of retiring models has sparked backlash. When the company withdrew GPT‑4o, users protested, citing the model’s “personality” and emotional connection. Petitions described GPT‑4o as a “best friend” or “a mirror.” Despite the outcry, GPT‑4o was deprecated in February 2026.
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