https://techcrunch.com/2023/08/22/openai-brings-fine-tuning-to-gpt-3-5-turbo/

OpenAI customers can now bring custom data to the lightweight version of GPT-3.5, GPT-3.5 Turbo — making it easier to improve the text-generating AI model’s reliability while building in specific behaviors.

OpenAI claims that fine-tuned versions of GPT-3.5 can match or even outperform the base capabilities of GPT-4, the company’s flagship model, on “certain narrow tasks.”