Thanks for the posting, but that does not answer my question at all. I already visited that thread before, and its related with the importing partners and things ... which seems not to be related with what im asking here --- import of leads within the kanban board of the odoo crm. Is this possible or not by default?

By default its not possible, Because cosider a customer A ask you for a service 1, then you create a lead, after a perticular time, the same customer A come to you for another service B. how you manage this. ! ?

If you need this you can do one thing, export the current leads. add the new records to the same Excel file. avoide the duplicate and re import all. i think this is one solution for your current issue.