We have completely changed the way data exports work. You still get the same result (spreadsheet data that you can use for whatever you like), but the screen to get your data exports is completely different.
The key reason we made this change was to handle the large amounts of data our customers are starting to build up in Cliniko. We needed to make sure our data exports are going to work even when you have hundreds of thousands of records.
The biggest advantage to this change for you is that Cliniko will now store and keep the data exports you have done, this can serve as "backups in time" if you use the data export regularly (even if you don't actually bring the data out of Cliniko, just leave the snapshots in there). This can be handy if you need to check back at how an invoice, appointment or payment looked before you made some changes, as long as you did an export previously, you will have that snapshot.
The new data export screen looks like this (and can be found in there settings area like before):