since a backup usually takes (even for a huge board) only 10mins or so.. i personally actually close the forum(s)..
but that's a personal choice...
there is no hard/fast rule that forums MUST be closed for a backup
If this whole thing takes me less than an hour, I will be surprised
So when I try the upgrade, I just follow the upgrade instructions
Except I add this part from the portal page here:
When upgrading, you'll want to update your libs/smarty and libs/phpmailer files from the download as these have been altered due to the compatibility issues mentioned above.