Advanced settings of mailing lists and Mailman archives are not transferred by Plesk Migrator.
Migration & Transfer Manager transfers only basic settings of mailing lists: list administrator, subscribers. Mailing list archives and other settings are not transferred, since Plesk cannot manage them.
It is possible to transfer configuration of mailing list using Mailman’s native utilities. Below example shows how to transfer settings of maillist maillist1 from one server to another:
On a source server, save mailing list configuration into file:
# /usr/lib/mailman/bin/config_list -o maillist1.conf maillist1
Transfer maillist1.conf to a destination server, where domain with mailing list has already been migrated and restore configuration:
# /usr/lib/mailman/bin/config_list -i maillist1.conf maillist1
If you want Plesk Migrator to transfer Mailman archives, we suggest to vote for this functionality on Plesk UserVoice.