Update OTRS and change queues

[CHJOTRS]

Hello guys ! I need your help

Actually I have got a 2.4.7 OTRS Helpdesk.
But queues need to be changed ("by product" queues => "by level of support" queues) and my company wants to update OTRS to the 3.1.

What is the easiest way to do :
- Install a new OTRS 3.1 with new queues and import an archive of old tickets.
- Update the actual 2.4.7 OTRS, put tickets in a "Temp" queue and change queues.
- Other ?

Thanks in advance

Jérémy