In reply to Carlos.

Same as usual: You click the button and it updates to 4.9.4.

The bug isn't in the updater, it's in the job that automatically runs the updater without you having to tell it, and it's in 4.9.3, not in the service. If you're still on an older version, you're not affected for two reasons:
1. Your site doesn't have the buggy code.
2. Your site isn't using automatic updates to begin with, or it would have updated to 4.9.3 by now.