GPT-5.5 Review 2026: OpenAI’s First Full Retrain Since GPT-4.5
In April 2026, OpenAI made history by releasing GPT-5.5—the first model since GPT-4.5 to receive a complete architectural rebuild from scratch. Every GPT-5.x release between 5.1 and 5.4 was merely a post-training iteration on the same base. GPT-5.5 breaks this pattern entirely, delivering a fundamental reimagining of how large language models are trained and deployed. … Read more