GitHub Changelog's March 19, 2026 X post announced that GPT-5.3-Codex is the first long-term support model for Copilot Business and Copilot Enterprise. GitHub says the model launched on February 5, 2026, stays available through February 4, 2027, and becomes the new base model by May 17, 2026.
GitHub Changelog said on April 3, 2026 that GPT-5.1 Codex, GPT-5.1-Codex-Max, and GPT-5.1-Codex-Mini were deprecated across all Copilot surfaces as of April 1. GitHub tells organizations to move workflows and model policies to supported models, with GPT-5.3-Codex named as the replacement.
On February 5, 2026, OpenAI launched Trusted Access for Cyber, an identity-verified program that gives defenders controlled access to enhanced cyber capabilities built on GPT-5.3-Codex. OpenAI paired the pilot with automated monitoring and a $10 million grant program for security researchers and infrastructure defenders.