Error 404 when downloading authenticated media

[milad2golnia]

Describe the bug
When enable_authenticated_media is set to true in Synapse (the new default as of Synapse 1.120+), media uploaded to the server is only accessible via the authenticated endpoints (/_matrix/client/v1/media/download/...). However, the matrix-bot-sdk currently appears to request media from older endpoints like /_matrix/media/v3/download/..., which yields a 404 Not Found for newly uploaded “authenticated” media.

To Reproduce

1. In Synapse’s homeserver.yaml, set enable_authenticated_media: true (or use a version of Synapse where it’s on by default).
2. Start a bot using matrix-bot-sdk.
3. Have a user upload an image or file to that server.
4. The bot calls downloadContent() or uses mxcToHttp(), which tries the legacy endpoint /_matrix/media/v3/download/....
5. Synapse returns 404 because the requested media is marked authenticated and no longer served on the old endpoint.

Expected behavior
Use the new /_matrix/client/v1/media/download/... endpoint automatically when requesting an authenticated media.

Log snippet
The bot receives 404 Not Found from Synapse when trying to download new media.

MatrixHttpClient (REQ-XX)
{
  "errcode": "M_NOT_FOUND",
  "error": "Not found"
}

Additional context
Refer to Synapse Docs for more information