After the upgrade I've run into a couple of annoying issues:

admin/cat_view.php - displays a blank page, so I can't edit any categories

admin/cat_set_default_price.php - throws a really "helpful" error:
Code:
Fatal error: Call to a member function FetchRow() on a non-object in /home/xxxx/xxxxxx/web/admin/cat_set_default_price.php on line 64

/admin/inv_unpaid.php - blank page

admin/inv_overdue.php - blank page

/admin/inv_paid.php - blank page