Volume subpath silently fails

[pikeas]

services:
    foo:
        image: ubuntu
        volumes:
            - type: volume
              source: bar
              volume: { subpath: baz }
              target: /baz

From https://github.com/moby/swarmkit/blob/master/swarmd/dockerexec/container.go#L338-L343:

if m.VolumeOptions != nil {
	mount.VolumeOptions = &enginemount.VolumeOptions{
		NoCopy: m.VolumeOptions.NoCopy,
		// TODO: uncomment after 26.0 vendor
		// Subpath: m.VolumeOptions.Subpath,
	}

Has Docker 26.0 been vendored? If so, please enable volume subpath support! If not, please emit an error message.