GPT-5.5 retirement
On October 14, 2026, GPT-5.5 will retire from ChatGPT, ChatGPT Work, and Codex on all plans, including consumer, Business, Enterprise, and Edu plans. This retirement does not apply to the OpenAI API.
If you use Codex with ChatGPT sign-in, choose an available replacement before October 14:
- On Plus, Pro, Business, Enterprise, and Edu plans, choose GPT-6 Sol
(
gpt-6-sol) when available. - On Free and Go plans, choose GPT-6 Luna (
gpt-6-luna) in the desktop app when available.
Replace gpt-5.5 in workspace defaults, saved model settings, managed
configurations, custom agents, scheduled tasks, and scripts that select a model.
See workspace model availability for administrator guidance.
Choose a model
In Work or Codex in the ChatGPT desktop app, use the model and reasoning control beneath the composer to choose an available model and adjust its reasoning effort.
Higher reasoning effort can improve results for complex tasks, but it takes longer and uses more tokens. Start with the default effort and increase it when the task needs deeper planning or analysis.
Ultra mode goes beyond a single-agent run. It uses subagents to accelerate complex work, making it useful for larger tasks that can be split across subagents.
Choose a model
These recommendations apply to ChatGPT Work on the web. Use the model and reasoning control beneath the composer to choose an available model and adjust its reasoning effort.
Higher reasoning effort can improve results for complex tasks, but it takes longer and uses more tokens. Start with the default effort and increase it when the task needs deeper planning or analysis.
Ultra mode goes beyond a single-agent run. It uses subagents to accelerate complex work, making it useful for larger tasks that can be split across subagents.
Choose a model
In an interactive CLI session, use /model to switch models or adjust
reasoning effort. You can also choose a model when you launch Codex with
--model or its -m alias:
codex --model gpt-6.1-solThe same option works with non-interactive runs. For example:
codex exec -m gpt-6.1-sol "Review the current changes"Higher reasoning effort can improve results for complex tasks, but it takes longer and uses more tokens. Start with the default effort and increase it when the task needs deeper planning or analysis.
Ultra mode goes beyond a single-agent run. It uses subagents to accelerate complex work, making it useful for larger tasks that can be split across subagents.
Choose a model
Use the model switcher below the composer to choose an available model and reasoning effort.
Higher reasoning effort can improve results for complex tasks, but it takes longer and uses more tokens. Start with the default effort and increase it when the task needs deeper planning or analysis.
Ultra mode goes beyond a single-agent run. It uses subagents to accelerate complex work, making it useful for larger tasks that can be split across subagents.
Recommended models
For complex coding and agentic workflows, use GPT-6.1 Sol when available to your
account and client. Use Luna for focused, repeatable tasks. Select gpt-6.1-sol
or gpt-6-luna in your model picker or saved configuration when available.
GPT-6.1 Sol offers near-Astra performance for complex work at a lower cost than Astra. See GPT-6.1 Sol for its separate rollout.
In ChatGPT, GPT-6.1 Sol, GPT-6 Sol, and GPT-6 Luna are available in Work and Codex. They aren’t available in Chat.
GPT-5.6 Sol, GPT-5.6 Terra, and GPT-5.6 Luna remain available during the rollout. Selecting a new model doesn’t change workspace permissions or grant access to it.
For Astra Ultrafast availability and credit usage on Pro $500 and eligible Enterprise and Edu plans, see Speed.
Our most capable model for complex work across code, apps, and research, combining advanced reasoning, computer use, and stronger judgment.
Near-Astra performance for complex work at a lower cost than Astra. Consider it for repeated, long-running work across code, apps, and documents.
Our most efficient model for focused, high-volume tasks, including summarization, extraction, and focused coding.
Availability depends on the rollout, your sign-in method, and your client. See pricing for plan access and usage, and workspace model availability for Enterprise access.
GPT-6.1 Sol
The GPT-6.1 Sol launch rollout includes Plus, Pro, Business, Enterprise, and Edu in Codex in the desktop app and CLI, and ChatGPT Work on the web and mobile. For Enterprise and Edu, the plan keeps GPT-6.1 Sol off by default until an administrator enables it. Free and Go are not included at launch.
Standard and Fast modes are available at launch. Ultrafast support for GPT-6.1 Sol is coming later.
Use gpt-6.1-sol. Available controls depend on your plan, client, and workspace
settings.
Reasoning effort ranges from Light to Ultra. Max and Ultra depend on your settings.
See pricing for credit usage and model selection for guidance on comparing it with Astra and Luna. To see how its API specifications differ from the previous Sol model, compare GPT-6.1 Sol and GPT-6 Sol.
In the ChatGPT desktop app and ChatGPT Work on the web, start with the default Power setting available to your account. Move toward Smarter for deeper reasoning or Faster for faster, lower-cost work. Open Advanced to choose a specific model, reasoning effort, or speed.
The six Power presets shown are Luna High, GPT-6 Sol Light (selected in this example), GPT-6 Sol Medium, Astra Light, Astra Medium, and Astra Extra High. Some paid plans omit Astra Extra High. Advanced controls are illustrative; available options and defaults vary by plan, client, workspace settings, and rollout.
Choosing a model
Choose Astra when a task needs the strongest capability across steps and tools. GPT-6.1 Sol offers near-Astra performance at a lower cost than Astra. Use GPT-6.1 Sol when available to your account and client, and Luna for clear, repeatable tasks.
Where each model shines
- Astra, for the hardest end-to-end work. Choose Astra for complete workflows across code, apps, and research that need sustained reasoning and judgment. Give it the sources, templates, constraints, and checks that define a useful result. Astra is better at asking focused questions and incorporating your guidance while keeping the original goal and constraints in view.
- GPT-6.1 Sol, for repeated, long-running work. Consider GPT-6.1 Sol for work across code, apps, and documents when cost matters. Keep Astra for your most demanding work.
- Luna, for clear, repeatable tasks. Choose Luna for specific, high-volume tasks when you know what a good result looks like, such as extraction, classification, transformation, and structured summaries.
Pick a reasoning effort
For GPT-6.1 Sol, start with the reasoning effort available by default in your
client and adjust based on the task. Start with High for Luna or Light
for Astra.
In configuration, Astra’s Light setting is low. Increase the effort for tasks
that need more planning, analysis, or checking.
- Light in the ChatGPT desktop app, ChatGPT Work on the web, and IDE extension, or Low in the CLI, suits quick, well-scoped tasks.
- Medium balances speed and depth for tasks that need more planning.
- High and Extra High suit difficult work with multiple steps, sources, or tradeoffs.
Reasoning efforts don’t map exactly between model generations. Try a familiar task at a lower setting and adjust based on the result.
Know when to use Max or Ultra
Max gives the selected model more time to reason about a single task. Use it for the hardest problems, when depth matters more than speed or usage. If you don’t see Max in the ChatGPT desktop app, check your app settings.
Ultra uses subagents to handle separate parts of a complex task in parallel. Choose it when you can divide the work into meaningful parts. Most tasks do not need Max or Ultra.
GPT-6 Luna supports reasoning efforts up to Max, but not Ultra.
In the CLI, use /model, choose a model, then select More reasoning…
to see its supported Max or Ultra options.
If your model supports Ultra but it doesn’t appear in the desktop app’s model slider, go to Settings > Configuration, then turn on Ultra in model picker slider.
Other models
When you sign in with ChatGPT, Codex works best with the recommended models listed above.
View other models
Previous-generation flagship model. Retires from ChatGPT, ChatGPT Work, and Codex on October 14, 2026; remains available on the OpenAI API.
For a custom model provider or gateway, use a compatible Responses API endpoint.
See Custom model providers
for configuration and Gateway compatibility
for streaming, tool, and conversation requirements. Current Codex releases don’t
support wire_api = "chat" or a Chat Completions-only endpoint.
Deprecated Codex models
GPT-5.3-Codex-Spark retired on September 14, 2026, and is no longer available
in the ChatGPT desktop app, Codex CLI, or IDE extension. Update saved
configurations, custom agents, and scripts that select gpt-5.3-codex-spark
to use an available model. See the
Spark retirement notice.
GPT-5.5 retires from Codex with ChatGPT sign-in on October 14, 2026. Replace
gpt-5.5 with a model available to your account and client. See
GPT-5.5 retirement for plan-specific
replacements and the migration checklist.
The gpt-5.4 and gpt-5.4-mini models retired from Codex with ChatGPT sign-in
on August 31, 2026. Replace gpt-5.4 with gpt-6-sol and
gpt-5.4-mini with gpt-6-luna when available to your plan and client.
In Enterprise and Edu, an administrator must enable Luna first. Update workspace
defaults, saved model settings, managed configurations, custom agents, and
scheduled tasks with an available replacement.
The gpt-5.2 and gpt-5.3-codex models are already deprecated in Codex when
you sign in with ChatGPT. Update scripts, configuration files, and
codex exec --model commands that still reference those models.
The OpenAI API and Codex authenticated with your own API key aren’t affected by the GPT-5.4 retirement. For current API model availability, see the API models page.
Configure your default local model
The ChatGPT desktop app, Codex CLI, and IDE extension use the same config.toml
configuration file. To specify a model, add a
model entry to your configuration file. If you don’t specify a model, the
ChatGPT desktop app, Codex CLI, or IDE extension uses a recommended model.
model = "gpt-6.1-sol"