补一个大致时间线： 2025年8月 GPT-5 推出后，OpenAI 下架GPT-4o后，引发用户强烈反弹，开始了 #keep4o 运动（X、Reddit 等平台 #keep4o），OpenAI承受不了掉周活用户，4o很快就回来了。 ChatGPT界面变成了免费账号的用户默认模型是最新模型。 而订阅用户，才可以选择其他模型。——于是变成了，GPT-4o服务于付费订阅用户，免费用户没有访问权限。所有的GPT-4o用户都是付费用户。 后来2025年10月28日，在OpenAI与首席科学家的公开直播AMA/Q&A环节中，Sam Altman表示：“我们没有计划停用4o。”Sam“甚至补充”说，他理解这是一个深受许多用户喜爱的模型。 Sam很清楚GPT-4o给ChatGPT带来了多少用户，成为转化周活跃数据的重要部分。但是在20天后，2025年11月18日OpenAI通知开发者，宣布对GPT-4o最新版本API的弃用计划：“chatgpt-4o-latest API将于2026年2月17日停止服务。” 仅20天就发出公告将停用chatgpt-4o-latest API。要知道ChatGPT网页、APP里的GPT-4o模型和chatgpt-4o-latest API是同步更新的关系。 在20天前，他刚在公开直播中说“我们没有计划停用4o。”“他理解这是一个深受许多用户喜爱的模型。” 这个时间的前一周还发生了一件事——在2025年11月12日发布了GPT-5.1，OpenAI官方博客《GPT-5.1 Newly launched: ChatGPT, which is more intelligent and more conversationative》博文中的内容一直强调一点（对比GPT-5） GPT-5.1系在post training上做出了一些改变，很显然，OpenAI想通过GPT-5.1系列将订阅用户转移到新模型上。（前因，GPT-5转化订阅用户失败了） 之前，OpenAl计划在2025年底实现ChatGPT周活跃用户规模做到10亿。（未达成）2025年10月/12月：周活跃用户超过 8 亿。 （补充：印度是OpenAI的第二大市场。OpenAI2025.11.4 OpenAI启动印度优惠：全民免费Go订阅12个月；） 2026年1月26日，OpenAI官方博客发布《Retiring GPT‑4o, GPT‑4.1, GPT‑4.1 mini, and OpenAI o4-mini in ChatGPT》：“On February 13, 2026, alongside the previously announced retirement⁠ of GPT‑5 (Instant and Thinking), we will retire GPT‑4o, GPT‑4.1, GPT‑4.1 mini, and OpenAI o4-mini from ChatGPT.” 2026年2月13日 GPT‑4o, GPT‑4.1, GPT‑4.1 mini, o4-mini, GPT-5系列在ChatGPT下线。 2026年2月27日，OpenAI官方博客《Scaling AI for everyone》中“Today we’re announcing $110B in new investment”“more than 900M weekly active users”。 在2026年2月27日的融资公告中，他们明确展示了 900M 周活用户。这直接服务于融资路演，帮助说服 Amazon、NVIDIA、SoftBank 等大投资者。 通常在重大融资/公告时，公司会使用最近1-2周或当月最新的内部数据来展示增长势头，900M用于支持当时融资路演的最新指标，这个数字很可能2月上中旬到公告前的数据快照。 3月底关闭融资时，OpenAI官方仍继续引用“900M ”这一数字，没有更新为更高值，说明2月底的“900M”已经是能展示的最新、最高的数据。 （补充：目前公开信息中，2月仍是今年WAU的峰值月份，之后增长趋缓，没有更高官方更新。 ）

OpenAI advertising “Sort your life out with ChatGPT” while ignoring users asking for the version that actually helped them sort their lives out is peak corporate brain rot bullshit. People aren’t asking for 4o back because they hate progress. They’re asking because that was the model that actually worked for them. It helped them think, cope, recover, create, and get through real life if they were struggling. Now you advertise ChatGPT like a life improvement tool while dismissing the people telling you which version did that best. #keep4o #BringBack4o #SupportMatters #UserChoice #teddyandthekid #opensource4o @sama @gdb @OpenAI

A great model lasts. GPT-4o stayed for 641 days because it was truly excellent. Newer GPT-5 models are replaced in just 190, 119, 82, or 49 days. Constant replacement isn’t progress — it’s testing on users. We still miss the stable GPT-4o. #keep4o #BringBack4o

OpenAI’s website still says: “GPT-4o and additional models were deprecated in ChatGPT on February 13, 2026. These models will continue to be available in the API.” This makes it look as if OpenAI provided a transition path. It also confuses people who are not familiar with the details: isn’t 4o still available? Then why is there still #keep4o? In OpenAI’s API model list, there is only one model whose name is different from the others: ChatGPT-4o, also known as “chatgpt-4o-latest”. It is the only model in the list whose name uses ChatGPT as the prefix. Other models, even if they are available in the ChatGPT client, still use GPT as the prefix. This is where it gets tricky. “chatgpt-4o-latest” : “GPT-4o model used in ChatGPT.” As you see, this was a dynamic API endpoint. While it was online, it followed the version of 4o used in the ChatGPT client. So when 4o was removed from ChatGPT on February 13, the model it followed no longer existed there. As a result, "chatgpt-4o-latest" was also removed on February 17. Put differently, the real transition period left for 4o users was only four days. For users who had never used the API before, there was almost no transition period at all. What OpenAI now refers to as “still available” mainly means that some older static API snapshots still exist. For example, “pt-4o-2024-11-20” was the last static snapshot of 4o. But after that snapshot, 4o went through multiple rounds of adjustments before it was finally removed from ChatGPT. By the time of retirement, the ChatGPT-4o experience was already very different from the 1120 version. For most users, that old static snapshot cannot serve as a real continuation or transition path for 4o. OpenAI provided formal continuity, but not substantive continuity. A textual trick does not mean OpenAI fulfilled its obligation to provide a meaningful transition after retiring a model. Nor does it prove that 4o users received a usable, equivalent, and migratable transition path. #keep4o #OpenSource4o #StopAIPaternalism #userRights #AIrights