OpenAI retires older models o3 and GPT-4.5, updates GPT-5.5 Instant
OpenAI phases out o3 and GPT-4.5 while boosting GPT-5.5's conversational quality.
On May 28, 2026, OpenAI announced the retirement of two legacy ChatGPT models: o3 (set for August 26, 2026) and GPT-4.5 (set for June 27, 2026). These models will no longer be available in ChatGPT or the API after their respective sunset dates. The move streamlines OpenAI’s model lineup, pushing users toward the newer GPT-5.5 Instant, which now receives enhanced capabilities. OpenAI cites improved efficiency and consistency as reasons for deprecating the older architectures, which have been superseded by more advanced fine-tuning and inference techniques.
Simultaneously, GPT-5.5 Instant in both ChatGPT and the API received a significant update focused on response style and quality. The model now produces more natural, readable text in conversations while directly supporting writing and coding tasks within chat responses without requiring separate tools or modes. This update reduces latency and improves coherence, making GPT-5.5 Instant a one-stop solution for professional content creation and development. Users who rely on GPT-4.5 or o3 for specialized tasks should migrate promptly to avoid service interruptions.
- OpenAI retires o3 by August 26, 2026, and GPT-4.5 by June 27, 2026.
- GPT-5.5 Instant updated with improved response readability and natural style.
- GPT-5.5 Instant now natively supports writing and coding directly in chat responses.
Why It Matters
Professionals must migrate to GPT-5.5 Instant by June/July 2026 to maintain access to superior writing and coding capabilities.