How to Update from v.7 on old Mac to v.8 on New Mac

My friend just set up her new iMac and migrated from the old one. Her (very) old iMac was running such an older OS that did not let her update to v.8 from within the app. She paid yearly. So before she downloads the latest version onto her new iMac, will she be able to use her Secret Key or other login info to access her data?

What is the best procedure to update to v. 8 and access her data?