how to import previous tickets in customer infor center

[BrianYin]

hi, everyone
is there anyone have this problem after update otrs from 3.1 to 3.2
in otrs 3.2, it has customer information center function sorted by customerid. However, this function starts over, all tickets created by customers before don't show in this module.
why is that? is there anyone can help me with this? howto import those tickets in this module?
Appreciate it!!