Upgrading from NOF 7 (standard version) to Essentials

I guess I'm not the first person to suffer this problem. I transferred the NOF7 site to a template as per the instructions, only to have the new version tell me that it couldn't open the file. Too old (like its owner perhaps). Is it possible to get an interim version of NOF that could bridge the gap, or are there any other ways of upgrading?

I appreciate that I'm a long way behind the curve here with NOF7, but what can I say, it kept on working and doing the job, so I kept on using it.

Any help or advice gratefully received.