This is the first time I noticed the ispconfig_update.sh now shows this note at the beginning: Note: On Multiserver systems, enable maintenance mode and update your master server first. Then update all slave servers, and disable maintenance mode when all servers are updated. I was not aware I should use maintenance mode when updating a multiserver system. And the How To Update -article does not mention it, either. https://www.faqforge.com/linux/controlpanels/ispconfig3/how-to-update-ispconfig-3/ I tried to post this as comment on that faqforge article, but got popup "Something went wrong, your comment has not been posted".
Using Maintenance Mode is a recommendation to avoid users changing the config while the multiserver setup is not fully updated as such changes might fail at that time when the database layout of master and slave nodes differs. If you use it or not depends mainly on if you have other users using ISPConfig during the update. Thank you for the notice. I'll update the FAQForge article to mention Maintenance mode there as well.
