Moving clients from 12.x to 14.x / different server / different ip

Hello guys,

We are in process of updating out SEPT from 12.x to 14.x. 

SEPT 12.x is located on windows server 2008 32bit, so we must move it to another (WS 2008 r2 64bit) server. 

We installed SEPT 14 to new server, but we have problem making it comunicate with clients.

Back up - restore solution is not working when using with different versions of SEP.

We are not using sql database.

Only solution i see is to install SEPT 12 to new server (WS 2008 r2 64bit), make it comunicate with clients and then, update to SEPT 14? 

Any other options?

Thanks