ChatGPT & Codex changelog

ChatGPT — February 20, 2026

v2026-02-20-cd00428b includes 0 new features and 0 fixes. 2 changes

Changed

  • Expanded context window for Thinking
  • ChatGPT now has a total context window length of 256k tokens (128k input and 128k max output) when you manually select Thinking. Previously it was 196k total tokens.
ChatGPT — February 20, 2026 — Release Notes