During a successful upgrade from 1.9.10+ to 2.0.1+, a warning appeared in red:

"Your site is using an old blog visibility setting, the blog visibility upgrade is recommended." (see screen shot 1)

"blog visibility upgrade" was a hot link to: http://vle.c.fun.ac.jp/moodle2/admin/bloglevelupgrade.php

I opened this link in a new tab and got an "Section error!" (see screen shot 2)

I closed this tab and let the upgrade continue in the original window. The upgraded completed successfully.

On logging into the upgraded site, I clicked on 'Notifications' and saw the same "blog visibility" warning (see screen shot 3). Again, clicking on the link leads to a "Section error!".

We have hardly used the blog feature, so I am not too worried - at the moment. But, if someone upgrading comes across this warning (recommendation) and clicks on the link, they could be taken out of the upgrade process, and believe that it has failed,