The history of my old Google chats from a few years ago, and my old Hangouts chats, is gone. I have checked all my Google accounts. On some accounts, only some chats have disappeared. On one old account, all the chat history is gone. I remember being able to pull up conversation records from several years ago by searching for some keywords just a few months ago. And now I search for the same words the logs don't come up any more.
Google seems to have recently completely changed the Gmail layout but why are my chat logs gone as a result? How do I get them back?