If you are upgrading from version earlier than v1.4, then your list data will be automatically migrated from the old list format to the new format. This will have no effect on your data, but may cause the upgrade to take longer than usual.
NB: If you have any customizations on the following lists, you will have to reproduce them on the new lists:
The old lists will be left in place after the upgrade (renamed with the suffix " (Old)"), to allow you to more easily reproduce your changes.
Once you are happy that the customizations have been reproduced (or you have no customisations), you can use the dialog in the Settings page to remove the legacy lists. See this manual page for more details: Upgrading Lists