GPT-6 Astra was not open to free ChatGPT users by 18 September 2026. OpenAI put it on paid plans and made GPT-5.6 Luna the default for Free and Go.
The market resolves on OpenAI's help centre model release notes or an openai.com announcement, published on the day of each rollout, stating by 23:59 BST on 18 September 2026 that GPT-6 Astra (under that name or a designated free-tier variant of it) is available to ChatGPT users on the free plan, with or without usage limits. If that source has not published in time, Reuters and the Guardian reports of the free-tier rollout. Silence on all three by the deadline resolves NO settle it.
Five of the last eight GPT versions reached free users in 15 days. We looked at every GPT version launched in ChatGPT since GPT-4o in May 2024 where an OpenAI page or a report from our approved sources said who could use it and when. For each one we asked if free ChatGPT users had a model of that version within 15 days of the announcement.