Is it sufficient to simply move a mail from/to the “Junk” folder to trigger the spam/junk filter to learn the change?
-AFAIK yes
Will this work with mail clients connected via IMAP and with SOGo?
-If you’ve subscribed to the correct folder, yes
Do I have to manually delete the mails in the “Junk” folder from time to time or will Mailcow do this on its own,
-end user have to do it
regarding to the settings of “Retentions per mailbox” & “Maximum age in days” as configured under Admin UI –> System –> Configuration –> Quarantine?
-Quarantined mails are not delivered to the mailbox nor junk foler
Could I delete the mails in the “Junk” folder manually without any side effects?
-AFAIK yes
If only Junk mails are moved to the “Junk” folder and there is no use of the Quarantine, will Spam Notification Mails (User UI –> System –> User Settings –> Mailbox –> Settings –> Quarantine notifications) make sense at all (if someone regularly checks the “Junk” folder)?
-Junk folder containes mail which may or may not spam. it’s up to you to decide. quarantined mails are in quarantine not on your mailbox
Is the Whitelist & Blacklist (User UI –> System –> User Settings –> Spam filöter –> Whitelist/Blacklist) only applied to Spam mails or also to Junk mails?
-in general to any mail. whitelist bypasses spamfilter and blacklist blocks the mail regardless of it’s content.
I have read multiple time here in the forum that the Spam filtering / Spam Quarantine is disabled by default. Which config option in Mailcow exactly does enable / disable the Spam filter?
-don’t know.