Google announced last year that it's shutting down Allo, its smart messaging app, in March 2019. Apparently, the time is now. A banner across Allo's official website clearly states that the app is saying goodbye on March 12th, and you'll have to export your chats if you don't want them to vanish into the ether. Allo's Help page says you can download your conversations and all the photos, videos and files in them by going into Chat under Settings. All your messages will be saved as a CSV file, while your media will be downloaded as a zip package.