Depending on the current version of Intelligent Sandbox on your appliance ensure that you download the right installation package.
The migration package is available for download from the Trellix download site.
Go to Product Downloads.
Enter the grant number.
Download the correct migration package:
Appliance
Package name
Trellix Intelligent Sandbox physical (ATD-3000/3100/3200 or ATD-6000/6100/6200) or virtual appliance
migration-5.2.X.X.XXXXX.msu