Hi Pankaj,
For fresh installation, you could export the configurations and projects from MII 12.1 server and then import into the fresh MII 14.0 server. This should work fine.
Also have a look at the MII 14.0 Upgrade Guide at the following location:
SAP Manufacturing Integration and Intelligence 14.0 – SAP Help Portal Page
You could also check the following threads as they are about the up gradation process:
Problem during migration from 12.2 to 14.0 sp4
Regards,
Rohit Negi.