OpenAI scheduled the removal of gpt-5.3-codex, gpt-5.4-nano, gpt-5.1 and older TTS models from its API

Archive entry: this covers an event from October 1, 2026, and we published it on November 8, 2026. The details come from sources dated at the time and may have changed since.

On October 1, 2026, OpenAI published removal notices for several models on its API deprecations page. It gave six months' notice that gpt-5.3-codex, gpt-5.4-nano and gpt-5.1 would be removed from the API on April 1, 2027, each with a GPT-6 replacement, and it scheduled the older text-to-speech (TTS) models for removal on January 6, 2027.

What was scheduled for removal

• gpt-5.3-codex was to be removed on April 1, 2027, with gpt-6-sol as the replacement.
• gpt-5.4-nano and gpt-5.4-nano-2026-03-17 were to be removed on April 1, 2027, with gpt-6-luna as the replacement.
• gpt-5.1 and gpt-5.1-2025-11-13 were to be removed on April 1, 2027, with gpt-6-sol as the replacement.
• tts-1, tts-1-hd and gpt-4o-mini-tts (2025-03-20 and 2025-12-15 snapshots) were to be removed on January 6, 2027, with gpt-realtime-2.1-mini as the replacement.

What it meant for people who build with AI

Apps built on these older GPT-5 models and on the classic TTS endpoints had firm migration deadlines. OpenAI gave six months' notice for gpt-5.3-codex, gpt-5.4-nano and gpt-5.1, so teams could plan a move to the named GPT-6 replacements, and the dated snapshots gpt-5.4-nano-2026-03-17 and gpt-5.1-2025-11-13 were covered by the same notices. Anything running on tts-1, tts-1-hd or gpt-4o-mini-tts had until January 6, 2027 to move to gpt-realtime-2.1-mini.

Sources

• Deprecations | OpenAI API (2026-10-01 notices) (OpenAI, October 1, 2026, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.