An interesting anecdote: they're installing Jitsi Meet in all Catalan prisons as we speak, as the go-to option now that visitors are no longer allowed, installed on the existing computers (i.e. prison libraries). They're planning to have Whatsapp setup too as a secondary option, because it's the option with widest reach, but that requires buying a bunch of new mobile phones. More details (in Spanish): https://elpais.…
An interesting related question would be what software are the different national cabinets, states presidencies and other high ranking officials etc using in their daily conferences.