# ChatGPT Updates Paid Sol and Schedules Unlimited Free/Go Luna Text

Times of AI Desk · 2026-08-06 · Models

[https://timesof.ai/2026/08/openai-gpt-5-6-sol-chatgpt-luna-free-tier](https://timesof.ai/2026/08/openai-gpt-5-6-sol-chatgpt-luna-free-tier)

> OpenAI retuned GPT-5.6 Sol for ChatGPT Plus/Pro with a thinking-effort slider and scheduled Luna as the Free/Go default, with unlimited text chats the following week. Internal evals claim ~68% / ~62% fewer factual-error responses vs GPT-5.5 Instant — company-run, not Arena or Artificial Analysis. Distribution day, not a new base-model family.

OpenAI updated Sol for Plus/Pro and scheduled a broader Luna text allowance for Free/Go. Unlimited Luna text was planned for the following week; paid users received the new thinking-effort slider at announcement.

**OpenAI** updated **ChatGPT** defaults across paid and free tiers. **Plus and Pro** get a **ChatGPT-tuned GPT-5.6 Sol** (separate from the Sol used in **Codex / ChatGPT Work**) plus a **thinking-effort slider** that replaces separate Instant vs Thinking modes. **Free and Go** were scheduled to get **GPT-5.6 Luna** as default that week, with **unlimited text chats** and a **Think** button planned for the following week. OpenAI says one **billion** people now use ChatGPT weekly.

## What changed by tier

| Tier | Model default | New controls | Notes (OpenAI + release notes) |
|------|---------------|--------------|--------------------------------|
| **Plus / Pro** | Updated **GPT-5.6 Sol** (ChatGPT path) | **Thinking slider** | More focused answers; less excess formatting; adapts detail to question difficulty |
| **Free / Go** | **GPT-5.6 Luna** | **Think** button for harder questions (rolling) | **Unlimited text chats** next (abuse guardrails remain); limits stay on files, images, voice, image gen, other tools |
| **Codex / Work Sol** | Unchanged | — | ChatGPT Sol retune is **product-path specific** |

## Claims vs checks

OpenAI reports an **internal evaluation** on finance, medicine, and law prompts requiring factual detail:

| Model | Claim vs **GPT-5.5 Instant** |
|-------|------------------------------|
| **GPT-5.6 Sol** (updated ChatGPT) | ~**68%** fewer responses with ≥1 factual error |
| **GPT-5.6 Luna** | ~**62%** fewer responses with ≥1 factual error |

These are **company-run** figures — not independent arena or third-party factuality boards. Treat as lab-reported until Artificial Analysis / Arena-style audits catch up.

This is a ChatGPT product-path update. OpenAI says the Sol version powering Work and Codex is unchanged. The launch’s internal factuality evaluation does not establish a new public leaderboard result.

## Limits

- Factuality cuts are internal only; no new public Elo.
- Unlimited free text may raise abuse/cost pressure — not measured here.
- Work/Codex Sol stays deliberately different from chat Sol.

**Correction (October 14, 2026):** Clarified that Free/Go unlimited text and the Think button were scheduled for the following week, and removed unsupported claims about historical rankings carrying over.

## Sources

- [OpenAI: ChatGPT Sol/Luna update (August 6, 2026)](https://openai.com/index/improving-gpt-5-6-sol-in-chatgpt/)