If you want zero downtime, there’s a couple extra steps that need to be done - disable “post-migrations” on the new containers, roll out the new container fully, enable post-migrations, then roll out again. This will stop any column-dropping migrations from executing until the old code is no longer running.
There’s no #howto for this yet, it’s only documented here:
For the most part, though, most forums can live with a minute or three of downtime every month.