So, i noticed my 5.5 Medium usage was going fast and I went to help to figure out what’s going on. 5.5 outside of Low is now 5.6 Sol, so if you think you’re using a lower cost model they happily switched you to the most expensive model at the reasoning you requested. Not Terra or Luna, which would make sense. Not a warning. Even if they sent an email, shouldn’t they remove the option? Their emails go into my Promotions Folder. I kind of feel robbed.
Welcome to the dev Community, @ShaggyBeats
Thanks for sharing your feedback. I can understand why this would be frustrating, especially if the change wasn't what you were expecting.
According to our Help Center, GPT-5.5 Instant is still available as the default model for fast, everyday responses. What's changed is that, on eligible plans, the Medium, High, and Extra High reasoning options are now powered by GPT-5.6 Sol. Terra and Luna aren't selectable in standard ChatGPT conversations - they're available in ChatGPT Work, Codex, and the API.
Thanks again for taking the time to share your thoughts and experience.
~ Smith