Due to issues with our anti spam measures, we had to migrate those mailing lists, that were sent from @archlinux.org before to the @lists.archlinux.org domain. Submission to the mailing list is not affected and still works with @archlinux.org. Mails get redirected automagically. The only change that may need to be considered on your side are filters and rules matching the From or List-id header which changed accordingly. URL: https://www.archlinux.org/news/arch-linux-mailing-list-id-changes/