This Fling has been productized and is now part of the vSphere 7.0 Update 1c release. For vSphere 6.x-to-6.x Migration, this Fling can still be used but for newer migrations, it is recommended that you use the official Advanced Cross vCenter vMotion feature included in vSphere 7.0 Update 1c. Please see History of Cross vCenter Workload Migration Utility and its productization in vSphere 7.0 Update 1c (p02).
Cross vCenter Workload Migration Utility
This Fling allows users to easily migrate virtual machines in bulk from a graphical user interface between vCenter Servers (same & different SSO Domains supported) using the Cross-vCenter vMotion feature.