OpenAI Hints at Major Release on September 22 — GPT-6 Sol and Luna Expected

OpenAI is preparing a major release for Tuesday, September 22, though the company has not yet revealed what it plans to unveil. Product Lead Thibault Sottiaux previously confirmed on X that the Tuesday launch remains on schedule.

Further fueling rumors, OpenAI employee Angel Brodin posted “I’m sol excited.” The pun on the name Sol quickly sparked speculation about an upcoming GPT-6 Sol launch, though the post is not an official model announcement. TestingCatalog itself also notes that the exact content of the release remains speculative for now.

As a result, it cannot yet be stated with certainty that OpenAI will release GPT-6 Sol, Luna, or multiple new models on September 22.

Sol and Luna Exist, but Currently Belong to GPT-5.6 Generation

The names Sol, Terra, and Luna are already used by OpenAI, but officially belong to the GPT-5.6 family.

Current Microsoft Azure documentation lists GPT-5.6 Sol, GPT-5.6 Terra, and GPT-5.6 Luna, whereas only Astra is officially listed in the GPT-6 generation so far. No models with API identifiers such as gpt-6-sol or gpt-6-luna have appeared in public documentation.

Therefore, references to GPT-6 Sol and Luna in third-party services, leaks, or internal registries are best viewed as strong indicators that new models are in preparation, rather than confirmed products.

The status of GPT-6 Astra Minor, which appears in circulating screenshots, is even less clear. OpenAI has not publicly presented such a model, and the presence of a name in a staging interface alone does not guarantee a future release.

GPT-6 Astra Launched in Early September

The first officially unveiled next-generation model was GPT-6 Astra, released by OpenAI on September 3.

The company positions it as its new flagship model for complex professional and agentic tasks, coding, computer use, scientific research, and cybersecurity. In the API, it is available as gpt-6-astra. OpenAI’s official announcement does not mention GPT-6 Sol or Luna as existing models.

Meanwhile, OpenAI’s materials repeatedly compare Astra to GPT-5.6 Sol, further confirming that Sol remains a previous-generation model at the time of publication.

Adding to the intrigue is the proximity of OpenAI DevDay 2026, set for September 29 in San Francisco. The company promises to showcase new APIs, tools, and technologies to developers, making a launch one week before the event plausible—though its exact contents remain unknown.

The key takeaway is to separate confirmed facts from rumors: OpenAI has indeed hinted at a major launch on September 22, but neither GPT-6 Sol nor GPT-6 Luna has been officially announced. The company has also not specified an exact release time.