no the "-u all" will update only the default DATaBASE in odoo

You must rebuild all databases individually with -u all when restarting the server. It is much cleaner ans safer to do one at a time. Make sure you have a backup of each.

Thanks for your rapid response, but what I mean is, without stop the server. I mean the scenario When You have like 20, then updated database you want, at night and in the morning they are ready, automatic, not one by one.

Thanks