The 409 Status Code is closely connected with version control. Resource versioning is tracked by such identifiers as ETag or If-Unmodified-Since headers used by systems. Should a client make an update, but the version identifier is not up to date, the server will reject the update with an HTTP Error 409 to avoid overwriting changes made by multiple clients. This is used to ensure the integrity of data and is one of the main applications of the Error 409.