Upgrading from version 1.2

Hi, I’m taking over an existing setup where a version 1.2 of nagios was responsible for monitoring the network hardware. The machine that it runs on is now having hardware difficulties (freezes after 10 minutes), so we want to install a more up to date version of nagios on a brand new server.

How difficult is this going to be and am I better off starting from scratch? I see in the various FAQ’s that going from version 1 to 2 involved a config converter, and then a different step to convert from 2 to 3. Also account for the fact that I’d be transplanting the config files rather than doing a proper upgrade on an existing and complete installation.