No migration from existing localStorage keys (introduced in 2.5.0 with N°1030) as the console UI has dramatically change in 3.0.0 : will be useful to show all the collapsible sections content once again !
Note that an iTop instance identifier was used in the localStorage key, it is no longer needed as we're getting the user pref directly from the current instance.
Thanks @Molkobain for the help !