In February, I noticed that the reading level feature had a bug and no longer allowed you to restrict results to "advanced reading level" pages. Instead of fixing the bug, Google removed yet another advanced search feature.
Reading level is no longer available in the search tools dropdown or in the advanced search page. Verbatim is the only remaining filtering option and I'm sure it will be removed soon. Hopefully, Google won't remove time filters, which are more popular and easier to understand.
Here are some screenshots from last month: