I had an idea for an app that would periodically access peoples' Facebook data. However, Facebook just deprecated the offline_access permission which prevents tokens expiring in a set time period.
Is there any way now for a 3rd party app to have continuous access to people's Facebook data (if they opt in, of course)?
Nope, Facebook wants your user to visit and interact with your app every 60 days. If your app is soooo bad that the user doesn't come back to it, Facebook doesn't really want your app to have access for indefinite time. So be a cool app and do something with it that has the user coming back periodically (before the 60 day limit) so you can get a fresh 60 day token. Happy coding!