Best Practices for Secure Yahoo Mail to Office 365 Migration

Good overview of the key security steps involved. One thing I'd add from experience, the pre-migration assessment part is often underestimated. A lot of teams skip auditing old mailboxes and then end up migrating years of junk, which slows everything down unnecessarily.

For the actual transfer, if anyone's looking for a DIY option, the EdbMails IMAP Migration Tool works well for Yahoo Mail to Office 365 moves. It handles the IMAP connection on the Yahoo side cleanly and lets you do incremental migrations, which is useful if you want to run both environments in parallel for a bit before fully cutting over. Keeps things lower risk.

The MFA point is spot on. Definitely don't wait until post-migration to enable that. Better to have it set up on the 365 side before the first mailbox lands there.