The model must be released by OpenAI or a successor to OpenAI. Staff at the company must commonly refer to the model as "GPT-7" or something else with "GPT-7" in the name.

For a model to be considered released, OpenAI (or its successor) must officially announce the model publicly and give access commercially to at least some users.

I'll use Eastern Time to determine the exact start and end times of each year.