ChatGPT Model Release Timeline: Year-by-Year Tracking of Iterations, Capability Leaps, and Rollout Cadence
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Apr 2026: OpenAI released GPT-5.5, its most capable and intuitive model for real-world work
ChatGPT Timeline Hub: Releases, Features, and Major Events
Table of Contents
The timeline is organized into three streams:
- Model Releases
- Feature Changes
- Major Events
How to use this timeline#
Start with Model Releases for capability milestones, then check Feature Changes for practical updates, and use Major Events for ecosystem context.
2026
ChatGPT Major Events Timeline: Industry Milestones by Date
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Late-Apr 2026 update: Codex phone-verification surge, Issue #20161 traction, and Advanced Account Security launch
ChatGPT Feature Changes Timeline: Product Updates by Date
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Added May 2026 release updates: Trusted contact in ChatGPT and memory sources with improved personalization.