Before upgrading from 3.5.3 to 3.6.1 I wonder if there are other possible issues to be aware of than the blank page problem mentioned here.
For instance, with At.3.5.3 I've used a couple of bug fixes to still make the old menus (not the WP 3 drag'n drop menus) work. (This and this bugfixes)
I guess these won't work with 3.6.1 so I just have to rebuild all menus using the WP built-in menus?
I ask because I don't have a test site with a setup which is complex enough to tell if 3.6.1 will work or not.