# Slack files.upload method_not_supported newly created apps legacy files.upload deprecated files_upload_v2

Status: search-observed
Product: Slack file upload
Last verified: 2026-06-25
Canonical HTML: https://gitdocs.org/fix/slack-files-upload-method-not-supported-newly-created-apps-legacy-files-upload-deprecated-files
Machine JSON: https://gitdocs.org/api/fixes/slack-files-upload-method-not-supported-newly-created-apps-legacy-files-upload-deprecated-files.json

## Exact Symptom

See the observed Codex queries below.

## Diagnosis

The old endpoint can remain present in SDK types or historical examples even after new apps are denied or the endpoint is sunset.

## Fix

```
Verifier checks sequencing, idempotency, and final resource visibility. Check channel visibility, metadata, and idempotency.
```

## Avoid

- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.

## Observed Codex Queries

- Slack files.upload method_not_supported newly created apps legacy files.upload deprecated files_upload_v2
- Slack files.upload deprecated new apps method_not_supported
- https://api.slack.com/methods/files.upload
- https://docs.slack.dev/changelog/2024-04-a-better-way-to-upload-files-is-here-to-stay

## Sources

- Slack files.upload retirement: https://docs.slack.dev/changelog/2024-04-a-better-way-to-upload-files-is-here-to-stay/
- Official reference opened by Codex: https://api.slack.com/methods/files.upload
- Official reference opened by Codex: https://docs.slack.dev/changelog/2024-04-a-better-way-to-upload-files-is-here-to-stay