OpenAI 2025-26 lineage

GPT is OpenAI’s family of language models

GPT models read instructions and produce answers, code and other work. OpenAI offers different sizes and reasoning settings, so the newest release date, price and product availability each answer a different question. The latest release in this timeline is GPT-6.1 Terra, introduced on 26 October 2026.

The family grew from GPT-5 to GPT-6.1

OpenAI’s API changelog records the following releases:

GPT-5.6’s Luna, Terra and Sol tiers sit between the GPT-5.5 and GPT-6 generations. The individual model pages cover their specifications and launch histories.

Current prices need their own date

On 5 October 2026, GPT-6.1 Sol costs $2 per million input tokens and $10 per million output tokens, with cached input at $0.10. Its model page sets additional rates for long prompts, faster processing and regional processing.

GPT-5.6 Sol’s promotional rate is $4 input and $20 output per million tokens, introduced on 21 August and scheduled to last through at least 21 November 2026. Its earlier $5/$30 launch price is a historical figure.

Product retirement and API retirement have separate dates

GPT-5.5 retired from Codex for users signing in with ChatGPT at 19:00 UTC on 14 October 2026. OpenAI API access and Codex sessions authenticated with an API key remain available. OpenAI’s model-access guide explains the distinction.

The API deprecation schedule separately sets 1 April 2027 for GPT-5.3-Codex, GPT-5.1 and GPT-5.4 nano. GPT-5.4-Cyber’s API shutdown date was 1 October 2026. Check the exact model ID in an application against that schedule before planning a migration.

API retirement dates need the exact model snapshot

OpenAI’s deprecation register, checked on 25 October 2026, records the shutdown of its listed legacy API snapshots on 23 October. Developers should match the full model identifier because snapshots within a family can have different retirement dates.

The 14 October notice gives 14 January 2027 as the shutdown date for GPT-4o snapshots dated 6 August and 20 November 2024, GPT-4o mini dated 18 July 2024, and GPT-4.1 and GPT-4.1 mini dated 14 April 2025. Fine-tunes follow their underlying base model’s schedule. The recommended replacement for those listed models is GPT-6 Luna.

The same register gives 6 January 2027 for its listed legacy text-to-speech models and 1 April 2027 for GPT-5.3-Codex, GPT-5.1 and GPT-5.4 nano. These are API schedules; ChatGPT product availability is recorded separately.