After updating the Facebook sdk to 3.5, when trying to perform openActiveSessionWithReadPermissions the operation fails. Here is the snippet for opening the session and hand
It seems that I had a URL Scheme that didn't match my FacebookAppId. For whatever reason this didn't seem to be a problem before but is relevant now. Make sure your Facebook URL Scheme is your FacebookAppID prefixed with fb (in your .plist files). For example:
FacebookAppId: 123456789012345
URL types -> Item 0 -> URL Schemes -> Item 0: fb123456789012345