We've added support for Segments with time-based rules (e.g., first session, last session, etc.) and also simplified targeting inactive users. Now you can target your inactive users by including a segment based on last session behavior.
Inbox Service Providers (ISP) like Gmail, Outlook, iOS Mail, and Yahoo! Mail, AOL, and Verison Mail require senders to provide a One Click Unsubscribe option. The unsubscribe button is rendered at the discretion of the ISP based on sending criteria, which may include a daily sending volume greater than 5,000 emails.