{"schema_version":"newruntime-agent-readable-v0.2","type":"post","stable_id":"post:codex-gpt-5-4-migration-boundary","slug":"codex-gpt-5-4-migration-boundary","title":"Codex Gets A Model Migration Deadline","description":"OpenAI's ChatGPT and Codex changelog sets an August 31, 2026 cutoff for GPT-5.4 and GPT-5.4 mini in ChatGPT-signed Codex sessions, while keeping API-key paths available.","retrieval_nugget":"OpenAI's ChatGPT and Codex changelog sets an August 31, 2026 cutoff for GPT-5.4 and GPT-5.4 mini in ChatGPT-signed Codex sessions, while keeping API-key paths available. OpenAI added a small but operationally important Codex deadline: on August 31, 2026, GPT-5.4 and GPT-5.4 mini will no longer be available in Codex for users signed in with ChatGPT.","status":"published","published_at":"2026-08-01","updated_at":"2026-08-01","record_date":"2026-08-01","date_kind":"published_at","topics":["codex","models","developer-tools","operations"],"source_urls":["https://learn.chatgpt.com/docs/changelog"],"visuals":[{"id":"codex-gpt-5-4-migration-boundary","kind":"editorial-diagram","role":"hero","src":"https://newruntime.com/images/posts/codex-gpt-5-4-migration-boundary.webp","alt":"Hand-drawn migration diagram where saved Codex defaults and scheduled tasks pass through a deadline gate into replacement model lanes while API-key sessions remain on a separate allowed path.","caption":"The GPT-5.4 cutoff is not a general disappearance; it is a boundary between ChatGPT-signed Codex defaults and API-key controlled sessions.","credit":"New Runtime synthesis from ChatGPT and Codex changelog","source_url":"https://learn.chatgpt.com/docs/changelog","generated_with":"gemini-3.1-flash-image","width":1600,"height":900,"legend":[{"label":"Deadline","description":"ChatGPT-signed Codex sessions lose GPT-5.4 and GPT-5.4 mini on August 31, 2026."},{"label":"Replacement","description":"OpenAI points GPT-5.4 users to GPT-5.6 Terra and GPT-5.4 mini users to GPT-5.6 Luna."},{"label":"API lane","description":"The OpenAI API and Codex sessions authenticated with an API key keep GPT-5.4 availability."}]}],"routes":{"html":"https://newruntime.com/posts/codex-gpt-5-4-migration-boundary/","markdown":"https://newruntime.com/posts/codex-gpt-5-4-migration-boundary.md","json":"https://newruntime.com/posts/codex-gpt-5-4-migration-boundary.json"},"source_format":"markdown","next_reads":[{"type":"topic","path":"/topics/codex/","reason":"Explore the codex topic hub.","url":"https://newruntime.com/topics/codex/","title":"Codex - New Runtime","media_type":"text/html"},{"type":"topic","path":"/topics/developer-tools/","reason":"Explore the developer tools topic hub.","url":"https://newruntime.com/topics/developer-tools/","title":"Developer Tools - New Runtime","media_type":"text/html"},{"type":"related_material","path":"/posts/codex-security-cli-scan-workbench/","reason":"Shares codex and developer tools.","url":"https://newruntime.com/posts/codex-security-cli-scan-workbench/","title":"Codex Security CLI Turns Security Review Into a Scannable Workbench","media_type":"text/html"},{"type":"related_material","path":"/posts/amazon-quick-agentic-catalog-context-boundary/","reason":"Shares developer tools.","url":"https://newruntime.com/posts/amazon-quick-agentic-catalog-context-boundary/","title":"Amazon Quick Makes Catalog Semantics The Agent Boundary","media_type":"text/html"},{"type":"related_material","path":"/posts/bcg-agentic-field-service-operating-loop/","reason":"Shares operations.","url":"https://newruntime.com/posts/bcg-agentic-field-service-operating-loop/","title":"Field Service Agents Need An Operating Loop, Not A Chat Window","media_type":"text/html"}]}