Facebook is one of those sites that is constantly updating their system. This IS a good thing, because they recognize that their system is not perfect.
I will be the first to admit that some changes they have brought in are things that really are odd and make things worse, not better, but with every change comes another instance when Facebook users should take the time to go through the settings to see what has been added and what has disappeared.
Facebook introduced a new interface for the web-based system a few months ago, and as of last month, the option to use the old interface disappeared. And last week, Facebook rolled out a new update to their mobile apps too. So, if you haven't already reviewed your privacy and security settings on the site, NOW is the time to do it.