Any kind of wildcard mail aliases (regex and/or /?) would be highly appreciated in order to realize a "allow form all but anything like..." handler. Example: Ban all info-@domain addresses.

I had somenting similar at my old provider but not with new one using plesk. Now I need to insert dozens (hundreds) of addresses one by one...

If there is already a way to realize something similar I was not able to find it (or my provider did not enable it)...

The possibility to archive/delete mail and then restore them afterwards.

The antispam filter could accept more than 100 addresses

There is a Mail Importing feature in Site Import extension, but it is possible only to migrate emails one by one. It would be great if there is an ability to migrate a couple of mailboxes at once.

Implement Dovecot LMTP.
Currently LDA is used for mail local delivery.
LMTP has a better performance and using it allows to avoid "Inotify instance limit for user (UID popuser) exceeded, disabling. Increase /proc/sys/fs/inotify/maxuserinstances" issues.

https://workaround.org/ispmail/jessie/postfix-dovecot

Horde already supports GPG encryption and key management. It would increase mail security a lot if it could be configured from plesk.

Hi!
It would be great if the autoresponder may switch on for a whole domain

Right now spf hook checks incoming mail for all domains if it is enabled in Tools & Settings > Mail Server Settings.
There is no simple way to disable it for some domains/subscriptions that may not need it present.

The ability to use nginx as mail proxy.

For example, as Postfix does not support SNI, such feature would be useful

https://docs.nginx.com/nginx/admin-guide/mail-proxy/mail-proxy/

Request to when a customer clicks to log in on the webmail it shows the options of webmail platforms he can select.

Example attached:

Please add functionality to configure redirection of single domain webmail.example.com to another URL

Currently, it is possible to apply it using the workaround:

https://support.plesk.com/hc/en-us/articles/360003509474-How-to-redirect-single-domain-webmail-example-com-to-another-URL

Hello,

Please add the possibility to purchase an extended license for mail servers with Plesk.

It would be helpful if I prefer to separate my mail services from my main hosting.

There is a harcoded delete_interval="30" in /usr/local/psa/admin/sbin/spamtrain. So nearly all my spam just got wiped and SpamAssassin has nothing to train with.

Please make this interval costumizable and deactivable.

Hello.

Currently Outgoing Mail Limit counts local forwarded messages from existing mail boxes:
https://docs.plesk.com/en-US/onyx/administrator-guide/mail/protection-from-outbound-spam.71349/

Please add functionality to exclude messages forwared to the local mailboxes from counting by Outgoing Mail Limit.

Currently Plesk Mail certificate only secure POP/SMTP and IMAP connections, would like a feature to encrypt outgoing messages itself.

In the email autoreply function, please extend the option to save corresponding texts for various situations (holidays, inventory, illness, sabbatical, etc.) and then select and edit them as needed. Many Thanks.

When creating backup of domain and using SmarterMail, contact lists are not backed up.

Please consider this option so that contacts are also backed up when performing a backup.

I suggest
Currently, the whitelist for each mail account is stored as individual lists. In groups (families, small businesses, clubs, etc. ) these lists are time-consuming to maintain. It is easier to maintain these as a matrix. So I suggest to keep the TAB "whitelist", but to link to a single central matrix file.

Please add functionality to forward an email to non-existent user to the sender on the email in example.com > Mail Settings > What to do with mail for non-existent users.