That’s interesting. Up until I looked today, based on your comment, HA’s website stated 2021.1.4, or at least I would swear by it. And now the advisory states 2021.1.3. What gives? So rhetorical question, why is it that my install stated to update the 2021.1.4. See my other post prior to my upgrade and initiating this thread which shows a screenshot of said version.
https://community.home-assistant.io/t/security-alert-ha-supervisord-wont-update/269277/4