The docker image was given some much needed love just prior to the 25.02 release.
See: https://forum.itflow.org/d/1364-anyone-want-to-help-work-on-the-docker-version/8
Its base was changed from Ubuntu to Alpine for a smaller disk and memory footprint.
Your existing Ubuntu container won't change over on its own, you would have to deploy a new container. You should be able to retain your database container as it hasn't really changed (Except for version updates) but if it insists on making a new one you can just map the data volume of your existing database container to the new one.
You should also grab your config.php file from the current itflow container to move over so it doesn't force you to go through the setup process again.