I'm sorry, I must have misunderstood backup and restore.
I thought it had to do with the mySQL database. Things like device templates, associated fields, etc. would be backed up then restored.
Your MD's would be restored without having to re-discover etc.
If you had made modification to a template, like adding a couple of more inputs to a TV then you'd lose that but standard fields would be there.
I didn't think it covered changes between operating systems upgrades, just database stuff.
I'd be pretty upset if I was running mySQL 4.0 and I'd have to manually input my database just because I upgrade to mySQL 5.0.
If I remember correctly 710 ran mySQL 5.0 and 810 is using mySQL 5.0, or, to paraphrase above, I don't know bodiddly about what backup and restore does - sorry.
I guess the next time I need to rebuild 8.10 I can at least try a backup and restore to see what happens on a 810 to 810 restore - best I can offer.