Device migration is the process of moving apps, settings, accounts, and data from one phone to another. In mobile environments, this can include photos and contacts, but also sensitive security state such as login tokens, messaging registrations, backup keys, and app permissions.
It matters in cyber security because a migration can quietly copy or drop the information that protects access. If old devices are not wiped, backups are not encrypted, or account re-registration is incomplete, attackers may recover data or keep access longer than intended. In real attacks, criminals may abuse weak transfer flows, stolen backups, or leftover trusted sessions. Defenders reduce risk by using encrypted transfer tools, requiring re-authentication after the move, verifying that security features still work, and removing trust from the old device once migration is complete. A successful migration should preserve usability without preserving unnecessary trust.