GPT-5.3 Features: 7 Hidden Upgrades in 2026 ChatGPT Update GPT-5.3 features are best understood as two different OpenAI releases: GPT-5.3-Codex for agentic coding and computer-based work, and GPT-5.3 Instant for everyday ChatGPT conversations. Their launch no... AI Models AI Tools 2026 ChatGPT 24-Apr-2026 0 255