8 Years since the original poster, I have pretty much the identical question. I last upgraded at UBB Classic 6.5.0 and now that has become unusuable thanks to the spam bots and the slow cgi-perl response time on my server.
So now I think I understand what I need to do at the highest level:
* download the UBB CLassic 6.7.3 upgrade zip from the members area
* unzip and tweak it locally, then carefully FTP it and configure it
Then, when that works
* Download the UBB classic 7.latest install zip from the members area
* unzip/install it (non-overallpingly, I guess)
* copy the 6.7 importer into the importers folder of my newly instally 7.latest
* configure it a little and let it import my 6.7.3 data into 7.latest
OK, fine. I'm sure it's completely straightforward, and this thread pointed me to the excellent documentation for the 6.7.3 upgradehttp://www.ubbcentral.com/support/docs/ubbclassic/UBB6_upgrade_within_6.html
Unfortunately, the members download area does not appear (in 2014) to have the "UBB CLassic 6.7.3 upgrade zip", just the full install zip, which includes a readme file explaining how it is NOT the upgrade zip and that using it is guaranteed to blow away all my data.
Now, when I paid my $139 just now, this was not apparent to me, since I had no access to the download area. That seems rather unfortunate. (Especially since this is my third full license, but it's been years and years and its all my own fault for not getting around to it before, so there is no one to blame but me, but still... it's unfortunate)
What I am asking here is:
* IS there any way to get the "UBB Classic 6.7.3 upgrade zip" ?
* If not, does it seem likely I can use the full install 6.7.3 that I just downloaded and carefully not overwrite my data? The 'upgrade 6.7.3 instructions look very helpful, unless they are completely inapplicable...
I know it will probably be another 10 years before the next 6.5.0 er comes out of the wqodwork, but it would have been more satisfying to know in advance if the situation really is "we no longer support upgrading from UBB Classic 6.5.0 while preserving your members and posts"
I hope that didn't sound snitty. I don't mean to be snitty, I want a happy ending, the spammers have pushed me to my limit.