Before this update, ChatGPT’s free tier using GPT-5.5 Instant was subject to a five-hour usage window and dynamic message limits. As more and more people rely on AI, OpenAI announced earlier that ChatGPT’s free tier now gets unlimited text chat; text chats are no longer bound by the original message limits, and both free and Go users will be able to use the latest GPT-5.6 Luna model without restrictions.
Additionally, OpenAI is also rolling out a reworked GPT-5.6 Sol for Plus and Pro users, along with a new thinking intensity slider that lets users decide whether ChatGPT should respond quickly or take a bit more time to think things through.
ChatGPT Update GPT-5.6 Sol: More Focused Responses, Free Tier Luna Now Offers Unlimited Text Chat
OpenAI recently rolled out a wave of user experience updates for ChatGPT. Paid users will get the adjusted GPT-5.6 Sol, while free users will gradually receive GPT-5.6 Luna, along with a chat experience that sets no limit on general text messages.
For those unfamiliar with the GPT-5.6 model, GPT-5.6 comes in three versions: Sol, Terra, and Luna. Sol is the flagship model with the most complete capabilities, Terra focuses on a balance between capability, speed, and cost, and Luna is the faster, lower-cost version.
This update primarily targets general chat conversations in ChatGPT. Plus and Pro users will receive the updated Sol, while free and Go users will gradually transition to Luna. As for GPT-5.6 Sol used in ChatGPT Work and Codex, OpenAI has stated that it will not be changed in this update.
So what changes does GPT-5.6 Sol have?
OpenAI says the new Sol has been recalibrated to match how people typically use ChatGPT, making responses more direct and focused, and it will decide how much to say based on the question itself.
For simple questions, I’ll give you the answer you need right away, without padding it with a long background intro just to look thorough. For multi-step planning, research, writing, or complex decisions, I’ll add the necessary analysis, but I’ll still put the main recommendation up front.
OpenAI also specifically mentioned that the updated Sol will reduce unnecessary formatting and excessive detail, and when users’ premises are incorrect, it will be more willing to offer corrections rather than simply going along with what the user says.
OpenAI also released a set of internal test results. Across financial, medical, and legal questions, GPT-5.6 Sol had 68% fewer responses containing at least one factual error than GPT-5.5 Instant, while GPT-5.6 Luna had 62% fewer.
Plus and Pro users now have a thinking intensity slider, letting them decide before asking whether the model should think more before answering, based on the difficulty of the question.
Plus and Pro users also now have a slider to choose how much reasoning effort ChatGPT puts into each response.
We think it’s easier to use, and we’re listening to your feedback. pic.twitter.com/u6HqhZpMts
— OpenAI (@OpenAI) August 6, 2026
If you’re just checking the weather, translating a sentence, or putting together a simple list, keeping the slider low is fine and responses will be faster. For research materials, writing structure, code debugging, itinerary planning, or decisions that involve multiple conditions, turn the thinking level up.
The new slider is available on the ChatGPT web version, mobile app, and desktop version.
As for the free tier, GPT-5.6 Luna will become the default model in ChatGPT for free and Go users, and it will offer unlimited text chat.
In the past, when using GPT-5.5 Instant on the free plan, you were limited to a 5-hour usage window, and once you ran out of credits, you had to wait for the system to reset. Now that it’s been switched to Luna, regular text conversations no longer require worrying about how many messages you have left. File uploads, image features, and other tools still have usage limits.
Free users will also get an extra Think button. When you feel Luna’s first response came too quickly, or the question involves multiple conditions, you can press Think to let the model take a bit more time to organize its answer.
Plus and Pro users can now start using the updated GPT-5.6 Sol and the reasoning intensity slider.
For free tier and Go users, they will gradually switch to GPT-5.6 Luna this week, with unlimited text chat and the Think button expected to roll out starting next week.
Source: KOCPC Chinese