@marquell-perkins I would suggest you download the demo and test it. I think there could be loading problems if you used old synth objects, effects and Vita Instruments that aren't part of Samplitude Pro X5 anymore. It is likely the best idea to export all your projects to WAV files. That should work without problems.
Since Pro X6 should release soon (probably in May) I would also suggest you to wait a little bit longer to get the newest version.
I notice that on "My Products" page, Samplitude x2 and x3 are not available for download anymore. Only the x3 serial number shows. Do I have to buy x5 for it to appear? Or else I'll download it from other sources