LinkedIn advanced search has changed with the new LinkedIn interface. Here's a short video showing you how to use the new search tool.
Many of the advanced search fields are still available which is great news. As I was testing the beta version of the new interface, LinkedIn said advanced search fields would only be available in Sales Navigator. Even if you paid for a Premium Business account, you would not have the advanced search fields. Today, I'm seeing the advanced search fields in the new interface.