5 months ago they said they hadn't started training: https://techcrunch.com/2023/06/07/openai-gpt5-sam-altman/ and had no intention to do so within the next 6 months: https://the-decoder.com/gpt-5-is-nowhere-close-says-openai-c...

They just started development in the last week or so: https://decrypt.co/206044/gpt-5-openai-development-roadmap-g...