OpenAI GPT-6 Model Version Divergence: ChatGPT on October Release, Codex and Work on September Snapshot
Following the October 7, 2026 launch of OpenAI GPT-6, official deployment documentation confirms that ChatGPT runs the October model version while Codex and Wor
Following the official launch of GPT-6 on ChatGPT on October 7, 2026, OpenAI's deployment documentation confirms that different products within the ecosystem are serving different snapshot versions under the unified "GPT-6" name.
Image source: https://deploymentsafety.openai.com/gpt-6-october/model-data-and-training
While marketed broadly under the single model identifier GPT-6, the web and mobile ChatGPT interface operates on an updated October version, whereas the developer-focused Codex tool and the enterprise Work suite continue to run the previous September version.
October vs. September Snapshots Across OpenAI Products
According to the official OpenAI Deployment Safety documentation (deploymentsafety.openai.com/gpt-6-october/model-data-and-training), the current GPT-6 model deployment is divided as follows:
- ChatGPT (Web and Mobile): Runs the October version model data and snapshot deployed on October 7, 2026.
- Codex (Developer Coding Harness): Retains the existing September version of GPT-6 rather than switching to the October release.
- Work (Enterprise Workspace Suite): Continues using the September version of the GPT-6 model data.
Although both environments present the model simply as "GPT-6" to users, the underlying weights and training data snapshots reflect different release cutoffs.
Practical Implications for Developer Workflows
This snapshot divergence explains potential variations in code generation, library familiarity, and reasoning output between ChatGPT and Codex.
When executing identical prompts across platforms, developers utilizing Codex as their primary environment and ChatGPT for auxiliary inspection may observe discrepancies in code formatting, newer API awareness, or response structure. A prompt tested and validated in ChatGPT's October environment may behave differently when executed inside Codex's September snapshot.
Based on official documentation, the version divergence is actively maintained, with no specific timeline announced yet for rolling out the October snapshot to Codex and Work products.