OpenAI

GPT-5.5 Is Here: A Quantum Leap in AI Capability # At the end of April 2026, OpenAI officially released GPT-5.5 — the most significant model iteration since GPT-5. For developers, this isn’t just a simple version bump — GPT-5.5 brings fundamental changes to reasoning depth, context handling, multimodal capabilities, and API design. This article dives deep into the technical details of GPT-5.5’s core upgrades, helping developers understand what this release means for their applications and how to migrate efficiently.