{"reviewedAt":"2026-11-14","scope":"Major text-chat model releases, previews, replacements and retirements during 2025 for the four discovery platforms. Variants launched together are grouped. API-only models, dated snapshots, Codex, and dedicated image/audio models are excluded. Dates indicate initial availability or the stated announcement date, not availability to every account. This curated timeline is context, not verified attribution of any collected conversation.","events":[{"id":"gemini-20-flash","platform":"gemini","date":"2025-01-30","kind":"release","title":"Gemini 2.0 Flash","description":"Rollout of 2.0 Flash in the Gemini web and mobile app. Older 1.5 Flash and Pro remained temporarily available for existing conversations.","source":"https://blog.google/feed/gemini-app-model-update-january-2025/","sourceLabel":"Google · Gemini app update"},{"id":"o3-mini","platform":"chatgpt","date":"2025-01-31","kind":"release","title":"o3-mini; o1-mini replaced","description":"o3-mini launched in ChatGPT and the API, replacing o1-mini in the ChatGPT model picker. Paid users also received an o3-mini-high option.","source":"https://openai.com/index/openai-o3-mini/","sourceLabel":"OpenAI · o3-mini announcement"},{"id":"gemini-20-pro","platform":"gemini","date":"2025-02-05","kind":"preview","title":"2.0 Pro & Flash Thinking","description":"Gemini 2.0 Pro Experimental rolled out to Advanced subscribers; Flash Thinking Experimental rolled out in the Gemini app. The same day's 2.0 Flash API release is separate from its January app rollout.","source":"https://blog.google/feed/gemini-app-experimental-models/","sourceLabel":"Google · Experimental models in Gemini"},{"id":"grok-3","platform":"grok","date":"2025-02-19","kind":"preview","title":"Grok 3 & Grok 3 mini","description":"Provider announcement for the Grok 3 beta family, including Grok 3 mini and reasoning modes. The marker uses the dated provider post; the unveiling began earlier that week.","source":"https://x.ai/news/grok-3","sourceLabel":"xAI · Grok 3 beta announcement"},{"id":"claude-37","platform":"claude","date":"2025-02-24","kind":"release","title":"Claude 3.7 Sonnet","description":"Claude 3.7 Sonnet introduced hybrid reasoning. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-3-7-sonnet","sourceLabel":"Anthropic · Claude 3.7 Sonnet"},{"id":"gpt-45","platform":"chatgpt","date":"2025-02-27","kind":"preview","title":"GPT-4.5 preview","description":"Research preview launched for ChatGPT Pro and developers, with access expanding to other paid plans afterward.","source":"https://openai.com/index/introducing-gpt-4-5/","sourceLabel":"OpenAI · GPT-4.5 announcement"},{"id":"gemini-25-pro","platform":"gemini","date":"2025-03-25","kind":"preview","title":"Gemini 2.5 Pro Experimental","description":"First 2.5 release, available in Google AI Studio and the Gemini app for Advanced subscribers.","source":"https://blog.google/innovation-and-ai/models-and-research/google-deepmind/gemini-model-thinking-updates-march-2025/","sourceLabel":"Google · Gemini 2.5 announcement"},{"id":"o3-o4-mini","platform":"chatgpt","date":"2025-04-16","kind":"release","title":"o3 & o4-mini","description":"o3 and o4-mini launched in ChatGPT and the API. In the paid ChatGPT model picker, o3, o4-mini and o4-mini-high replaced o1, o3-mini and o3-mini-high.","source":"https://openai.com/index/introducing-o3-and-o4-mini/","sourceLabel":"OpenAI · o3 and o4-mini announcement"},{"id":"gemini-25-flash","platform":"gemini","date":"2025-04-17","kind":"preview","title":"Gemini 2.5 Flash preview","description":"2.5 Flash entered preview in the API and became available in the Gemini app, combining fast responses with optional reasoning.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-2-5-flash-preview/","sourceLabel":"Google · Gemini 2.5 Flash preview"},{"id":"gpt-4-retirement","platform":"chatgpt","date":"2025-04-30","kind":"retirement","title":"GPT-4 retired from ChatGPT","description":"GPT-4 was removed from ChatGPT and replaced by GPT-4o. This retirement applied to ChatGPT; GPT-4 remained available through the API at that time.","source":"https://help.openai.com/en/articles/6825453-chatgpt-release-notes","sourceLabel":"OpenAI · April 10 release notes (effective April 30)"},{"id":"gpt-41","platform":"chatgpt","date":"2025-05-14","kind":"release","title":"GPT-4.1 & 4.1 mini in ChatGPT","description":"GPT-4.1 arrived in paid ChatGPT plans; GPT-4.1 mini replaced GPT-4o mini. Their April 14 API launch is not the ChatGPT availability date.","source":"https://help.openai.com/en/articles/9624314-model-release-notes","sourceLabel":"OpenAI · May 14 model release notes"},{"id":"claude-4","platform":"claude","date":"2025-05-22","kind":"release","title":"Claude Opus 4 & Sonnet 4","description":"Anthropic introduced the Claude 4 generation. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-4","sourceLabel":"Anthropic · Introducing Claude 4"},{"id":"o3-pro","platform":"chatgpt","date":"2025-06-10","kind":"release","title":"o3-pro","description":"o3-pro became available to Pro users in ChatGPT and through the API, using more compute for difficult questions.","source":"https://openai.com/index/introducing-o3-and-o4-mini/","sourceLabel":"OpenAI · June 10 update to o3 announcement"},{"id":"gemini-25-stable","platform":"gemini","date":"2025-06-17","kind":"release","title":"Gemini 2.5 Pro & Flash stable","description":"The 2.5 Pro and Flash models became stable and generally available. This follows their earlier experimental and preview releases.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-2-5-model-family-expands/","sourceLabel":"Google · Gemini 2.5 family expands"},{"id":"grok-4","platform":"grok","date":"2025-07-09","kind":"release","title":"Grok 4 & Grok 4 Heavy","description":"Grok 4 launched for SuperGrok and Premium+ subscribers, alongside Grok 4 Heavy through the new SuperGrok Heavy tier.","source":"https://x.ai/news/grok-4","sourceLabel":"xAI · Grok 4 announcement"},{"id":"gemini-deep-think","platform":"gemini","date":"2025-08-01","kind":"release","title":"Gemini 2.5 Deep Think","description":"Deep Think rolled out in the Gemini app for Google AI Ultra subscribers.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-2-5-deep-think/","sourceLabel":"Google · Deep Think in the Gemini app"},{"id":"claude-41","platform":"claude","date":"2025-08-05","kind":"release","title":"Claude Opus 4.1","description":"An update to Opus 4 focused on agentic tasks, coding and reasoning. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-opus-4-1","sourceLabel":"Anthropic · Claude Opus 4.1"},{"id":"gpt-5","platform":"chatgpt","date":"2025-08-07","kind":"release","title":"GPT-5, Thinking & Pro","description":"The GPT-5 system launched in ChatGPT, including reasoning and Pro access. Later legacy-model availability varied by plan; this marker does not claim a permanent retirement of every preceding model.","source":"https://openai.com/index/introducing-gpt-5/","sourceLabel":"OpenAI · Introducing GPT-5"},{"id":"grok-4-fast","platform":"grok","date":"2025-09-19","kind":"release","title":"Grok 4 Fast","description":"A faster model with reasoning and non-reasoning modes, introduced across consumer and developer products.","source":"https://x.ai/news/grok-4-fast","sourceLabel":"xAI · Grok 4 Fast announcement"},{"id":"claude-sonnet-45","platform":"claude","date":"2025-09-29","kind":"release","title":"Claude Sonnet 4.5","description":"A new Sonnet version emphasizing coding, agents and computer use. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-sonnet-4-5","sourceLabel":"Anthropic · Claude Sonnet 4.5"},{"id":"claude-haiku-45","platform":"claude","date":"2025-10-15","kind":"release","title":"Claude Haiku 4.5","description":"Haiku 4.5 launched as Anthropic's small, fast model and became available to all Claude users. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-haiku-4-5","sourceLabel":"Anthropic · Claude Haiku 4.5"},{"id":"gpt-51","platform":"chatgpt","date":"2025-11-12","kind":"release","title":"GPT-5.1 Instant & Thinking","description":"GPT-5.1 began rolling out in ChatGPT, starting with paid accounts. GPT-5 remained temporarily available as a legacy option.","source":"https://openai.com/index/gpt-5-1/","sourceLabel":"OpenAI · GPT-5.1 announcement"},{"id":"grok-41","platform":"grok","date":"2025-11-17","kind":"release","title":"Grok 4.1","description":"Public announcement and explicit model-picker availability of Grok 4.1. xAI also reports a silent rollout of preliminary builds from November 1–14.","source":"https://x.ai/news/grok-4-1","sourceLabel":"xAI · Grok 4.1 announcement"},{"id":"gemini-3","platform":"gemini","date":"2025-11-18","kind":"preview","title":"Gemini 3 Pro","description":"Gemini 3 Pro began rolling out in the Gemini app. A launch marks a change in available models, not the generating model of a recovered conversation.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-3-gemini-app/","sourceLabel":"Google · Gemini 3 in the app"},{"id":"gpt-51-pro","platform":"chatgpt","date":"2025-11-19","kind":"release","title":"GPT-5.1 Pro","description":"GPT-5.1 Pro rolled out to ChatGPT Pro subscribers. GPT-5 Pro remained available as a legacy model for a stated 90-day transition.","source":"https://help.openai.com/en/articles/6825453-chatgpt-release-notes","sourceLabel":"OpenAI · November 19 release notes"},{"id":"claude-opus-45","platform":"claude","date":"2025-11-24","kind":"release","title":"Claude Opus 4.5","description":"Opus 4.5 launched across Claude apps and the API. Shown for historical context; no Claude transcripts were recovered in this collection.","source":"https://www.anthropic.com/news/claude-opus-4-5","sourceLabel":"Anthropic · Claude Opus 4.5"},{"id":"gemini-3-deep-think","platform":"gemini","date":"2025-12-04","kind":"release","title":"Gemini 3 Deep Think","description":"Gemini 3 Deep Think mode began rolling out in the Gemini app for Google AI Ultra subscribers, following the November launch of Gemini 3 Pro.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-3-deep-think/","sourceLabel":"Google · Gemini 3 Deep Think availability"},{"id":"gpt-52","platform":"chatgpt","date":"2025-12-11","kind":"release","title":"GPT-5.2 Instant, Thinking & Pro","description":"GPT-5.2 began rolling out in ChatGPT, starting with paid plans, with Instant, Thinking and Pro variants.","source":"https://openai.com/index/introducing-gpt-5-2/","sourceLabel":"OpenAI · Introducing GPT-5.2"},{"id":"gemini-3-flash","platform":"gemini","date":"2025-12-17","kind":"release","title":"Gemini 3 Flash","description":"Gemini 3 Flash began rolling out in the Gemini app as Fast and Thinking options. Gemini 3 Pro remained available in the model picker.","source":"https://blog.google/products-and-platforms/products/gemini/gemini-3-flash-gemini-app/","sourceLabel":"Google · Gemini 3 Flash in the app"}]}