[ChatGPT Announces GPT-5.5 Model to Be Discontinued Starting October 14] OpenAI has announced that the GPT-5.5 model will be fully removed from ChatGPT, ChatGPT Work, and Codex starting October 14. The official recommendation is for developers and teams still using GPT-5.5 in Codex to migrate to GPT-5.6 Sol or GPT-6 Astra as soon as possible to avoid service interruptions or changes in capabilities.