GPT-5.4 changelog

Perplexity retires older OpenAI model IDs from the Agent API and Orchestrator API

The changelog scheduled seven older OpenAI model IDs to retire on October 24, 2026 at 00:00 UTC. After the cutoff the IDs are no longer accepted or returned by model-list endpoints.

Who is affected:

Developers who select these OpenAI models directly or in fallback chains in the Agent API or Orchestrator API.

Action needed:

Switch direct model selections and fallback chains to a current OpenAI model such as openai/gpt-6-luna or openai/gpt-6-sol.

GPT-5.4 and GPT-5.4 mini retired from Codex

gpt-5.4 and gpt-5.4-mini retired from Codex with ChatGPT sign-in on August 31, 2026. The Codex models page now lists gpt-6-sol and gpt-6-luna as replacements.

Who is affected:

Codex users signed in with ChatGPT.

Action needed:

Replace gpt-5.4 with gpt-6-sol and gpt-5.4-mini with gpt-6-luna.

GPT-5.4 and GPT-5.4 mini leave Codex on August 31

GPT-5.4 and GPT-5.4 mini will no longer be available in Codex for ChatGPT sign-in from August 31, 2026. They stay on the API. Replacements named were GPT-5.6 Terra and GPT-5.6 Luna.

Who is affected:

Codex users signed in with ChatGPT who use GPT-5.4 or GPT-5.4 mini.

Action needed:

Update workspace defaults, saved settings and scheduled tasks before August 31.

OpenAI models available in Amazon Bedrock

GPT-5.4 and GPT-5.5 became available in Amazon Bedrock through an OpenAI-compatible Responses API endpoint, with models and features varying by AWS Region.