ChatGPT Desktop 26.715.21316 cannot resume paginated Codex thread created with app-server 0.150.0

Description

After updating to ChatGPT Desktop 26.715.21316 on Windows, an existing long-running Codex thread can no longer be opened.

The desktop app repeatedly fails while calling thread/resume with:

paginated threads do not support initialTurnsPage; use turnsBackwardsCursor and itemsBackwardsCursor

The persisted thread data still exists locally and appears intact.

Environment

• OS: Windows 10 Home 22H2 x64
• OS build: 19045.6466
• App: ChatGPT Desktop — Powered by Codex & OWL
• Desktop app version: 26.715.21316
• Desktop release date shown in About: July 17, 2026
• Bundled app-server after the update: codex-cli 0.145.0-alpha.18
• App-server used successfully before the update: 0.150.0-alpha.12.2
• Model used by the affected thread: gpt-5.6-sol
• Timezone: UTC+8

The thread ID, local paths, usernames, project content, and full logs are intentionally redacted.

Timeline

1. The long-running thread worked normally before the desktop update.
2. Before the update, desktop logs reported:

   Current reported app-server version: currentVersion=0.150.0-alpha.12.2
   

3. Immediately after updating, the desktop app started:

   Current reported app-server version: currentVersion=0.145.0-alpha.18
   

4. Opening the existing thread then began failing consistently.
5. The first confirmed failures were observed on 2026-08-29 around 17:40 UTC+8.
6. Fully restarting the desktop app produces the same error.

Steps to reproduce

1. Use a sufficiently long Codex thread that has been converted to paginated storage by app-server 0.150.0-alpha.12.2.
2. Update to ChatGPT Desktop 26.715.21316, bundled with app-server 0.145.0-alpha.18.
3. Open the existing thread from the desktop sidebar.
4. Observe that thread/resume fails repeatedly.

Actual behavior

The conversation does not open. Sanitized desktop logs contain:

Request failed
method=thread/resume
errorCode=-32600
error="paginated threads do not support initialTurnsPage; use turnsBackwardsCursor and itemsBackwardsCursor"

Failed to resume conversation
errorMessage="paginated threads do not support initialTurnsPage; use turnsBackwardsCursor and itemsBackwardsCursor"

Expected behavior

The desktop client should detect paginated thread storage and resume using the paginated protocol:

• excludeTurns: true
• turnsBackwardsCursor
• itemsBackwardsCursor
• thread/turns/list
• thread/items/list

It should not send initialTurnsPage for a paginated thread.

Additional findings

• The failure started only after the desktop update.
• The update effectively changed the app-server used by Desktop from 0.150.0-alpha.12.2 to the older 0.145.0-alpha.18.
• A cached 0.150.0-alpha.12.2 executable still exists locally, but the updated desktop app launches the bundled 0.145.0-alpha.18.
• Multiple rollout JSONL files for the affected thread and the local Codex SQLite database still exist.
• No cache, thread database, or rollout file was deleted or manually modified.
• This appears to be a desktop-client/app-server protocol compatibility regression rather than corrupted thread data.

Relevant protocol documentation

The current app-server documentation states that paginated threads require excludeTurns: true and backwards cursors, while full-history resume and initialTurnsPage are unavailable:

https://github.com/openai/codex/blob/main/codex-rs/app-server/README.md

Impact

A multi-day production development thread is inaccessible from the desktop UI immediately after updating. Starting a new thread loses interactive continuity and project context.

Related issues

• #33786 — large paginated thread/Desktop history behavior
• #25215 — long threads becoming unrecoverable after Desktop updates

This report is narrower: the server returns a deterministic -32600 protocol error because Desktop sends initialTurnsPage for an already-paginated thread after the bundled app-server version changes.

Start with codex-rs/app-server/README.md and the thread/resume entry point, then trace how paginated threads are detected and how turnsBackwardsCursor, itemsBackwardsCursor, and excludeTurns are handled. Reproduce with the supplied version transition and verify that paginated threads resume without initialTurnsPage, using thread/turns/list and thread/items/list as needed.