Unfortunately Dirac live projects are tied to the product type (as per licensing requirements). Although on the miniDSP, we are able to use the same DSP/plugin configuration, it's unfortunately not possible on the Dirac live side as projects won't be compatible and Dirac Live software won't allow you to load a DDRC-24 Dirac project file into your Flex.
To sum it up if you're upgrading from a DDRC-24, simply start a new Dirac Project with your Flex unit. It doesn't take that long to run your measurements. If you want to apply the same target curve, you can always do so with the SAVE/LOAD target curve feature Dirac Live.