One thing that LeapFrog sell is cartridge games, and other educational content, which are usually usable across different products in the entire LeapFrog range. This does mean that a cartridge can still be used with newer tablets.
The LeapFrog Epic, however, lacks a cartridge slot. Consequently, any old LeapFrog cartridges that were purchased for previous LeapFrog educational tablets are not compatible with the Epic. The games and other content are still available for the Epic, but these are now only available in app form from the LeapFrog App Centre. If existing games are wanted to be used with the Epic, they will need repurchasing in app form. Given the price of LeapFrog cartridges, and apps, this is definitely not a plus for those who already own a lot of cartridges.