GPT (original)
Release (see availability)Research release combining pretraining and fine-tuning; retrospectively GPT-1.
Historical event; see the access limitations above. Current support is not implied.
OpenAI · GPT models version history
Dates refer to release events, not our crawl or news publication times. Announcement, preview and availability can happen on different days. This is a curated record, not an exhaustive catalogue or a guarantee of the latest version.
Selected major model-family releases through October 1, 2026. Not comprehensive: most size variants, snapshots, specialized models and retirements omitted. Applications such as ChatGPT and Gemini app are separate products. Preview and GA events remain separate.
Sources checked through
Direction: oldest → newest · Earliest documented event · Most recent documented event
GPT-2
Release (see availability)Staged research release; only a smaller checkpoint initially, not the largest model.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-3
Announcement175B-parameter few-shot research announcement; not the API launch date.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-3 API access
Preview / limited accessDevelopers could request private-beta API access, separate from research announcement.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-4
Release (see availability)Improved reasoning; ChatGPT Plus access and API waitlist. Not every announced modality available.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-4 Turbo
Preview / limited access128K context and lower pricing; preview for paying API developers, not stable GA.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-4o
Release (see availability)Omni model; text/image input and text output first in ChatGPT/API. Other modalities staged later.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-4.5
Preview / limited accessChat-focused research preview for Pro users and developers; other plans staged.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-4.1
Release (see availability)API launch of 4.1/mini/nano, stronger coding and 1M context; not ChatGPT release. After 4.5.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5
Release (see availability)Integrated fast responses and reasoning; ChatGPT rollout and API release. Routed app and API models differ.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.1
Release (see availability)Instant/Thinking conversation and adaptive reasoning; ChatGPT rollout began with paid users; API next day.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.1 API
Release (see availability)API release with adaptive reasoning and efficiency; distinct from November 12 ChatGPT event.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.2
Release (see availability)Professional work, long-context reasoning and multi-step agents; API and staged ChatGPT rollout.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.3 Instant
Release (see availability)Improved everyday conversation, web synthesis and accuracy; ChatGPT/API gpt-5.3-chat-latest. Codex chronology separate.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.4
Release (see availability)Mainline reasoning, coding and professional work; released across ChatGPT, API and Codex.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.5
Release (see availability)Coding, computer use and professional work; ChatGPT/Codex rollout. API followed April 24, not April 23.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.6
Preview / limited accessSol/Terra/Luna restricted preview for selected partners through API/Codex; GA followed July 9.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-5.6
General availabilityGeneral availability of Sol/Terra/Luna across ChatGPT, Codex and API; gradual rollout over 24 hours.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-6 Astra
Release (see availability)Flagship reasoning and coding; phased rollout beginning with limited organizations, not simultaneous all-plan access.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-6 Sol and Luna
Release (see availability)Additional faster and lower-cost GPT-6 tiers; distinct from Astra and 6.1 Sol.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this eventGPT-6.1 Sol
Release (see availability)Improved coding/computer use/professional work; ChatGPT Work, Codex and API at launch, not Chat. API changelog confirms date.
Historical event; see the access limitations above. Current support is not implied.
Official sources
Link to this event