They also upgraded the GPT-4.1 (actually a special Apple variant) to GPT-5 by default, with the option to use GPT-5-thinking, using your ChatGPT subscription. I don't know if it's a special Apple variant of GPT-5 but this is a big upgrade and more exciting than Sonnet 3.7.
I also wonder if it will have separate rate limits from ChatGPT (app/web) and Codex CLI (which currently has its own rate limits).