Thanks 'A'!
I reached out to OnSSI yesterday - but Cynthia's issue falls somewhere between their support and pre-sales departments. She spoke with support and they gave her the documentation to complete the upgrade task... and OnSSI's presales technical team does not handle anything 'in production'.
OnSSI suggested to me that an upgrade from NetDVMS to RC-C 7.0 is something that should include Cynthia's OnSSI integrator partner. This is exactly the type of technical services issue that they are trained to provide to their end user customers.
OnSSI also suggested that the upgrade is an 'in place' upgrade - which is why they sent Cynthia the documentation to complete the task... however, if Cynthia is going to attempt the upgrade alone, I (personally) would tend to agree with Undisclosed A who suggests:
"Are you doing an in-place upgrade or are you migrating servers? I suggest migrating to new hardware to enhance the performance and allow you to protect the recorded video if needed." (my bold)
and
"I suggest getting an integrator to come in and advise on the nest solution for you. if you dont trust an integrator hire a consultant to oversee the job."
It's all about the data and your acceptable levels of 'risk'.
If the data must be retained, then lower your risk (of losing data) by copying the database, migrating to new hardware etc - before upgrading.
If the original database isn't needed, then you can 'risk' losing it by doing an in-place upgrade DIY style.
*I will add that, from my experience, in-place recording server upgrades are generally painless - unless there is an existing database issue on the original server that could cause problems with the upgrade process.