Codex desktop: GPT-5.6 shows unknown model gpt-5.6-sol while GPT-5.5 works

Codex
1

Hi everyone,

I’m seeing an issue in the Codex desktop app where GPT-5.6 is unavailable.

Environment:

  • Windows 11
  • Codex desktop app Version 26.707.31428
  • GPT-5.5 works normally

What happens:
When I try to use GPT-5.6, Codex returns:
unknown model gpt-5.6-sol

Expected:
GPT-5.6 should be available/usable in Codex, or the app should explain why it is not available for my account/environment.

I attached a screenshot showing the error.

Has anyone else run into this, or is there something I should update/check on my side?

codex-gpt-5-6-unknown-model.png
codex-gpt-5-6-unknown-model.png1000×238 2.75 KB

2

Yeah that is true, this launch is messed up. Currently on Plus sub and I am not able to see GPT 5.6 at all in the chatgpt chat app nor the sol model in the codex app. They shoud fix this. You can create a support ticket but that is all, waiting is the only option left :confused:

3

Thanks for reporting this, @Jostko and @1DogeProgrammer. GPT-5.6 is currently being rolled out gradually, as noted in the announcement, so it may not have fully propagated to your workspace yet.

Since GPT-5.5 is working, there likely isn’t anything you need to change on your side. It may just take a little more time before GPT-5.6 becomes available in Codex and ChatGPT.

-Mark G.