QUESTION: Transferring saves from 5.50 PS4 to 5.05 PS4

I have 2 PS4s, one with 5.50 FW and the other with 5.05 FW. I am looking to fully update the 5.50 PS4 and sell it, however i would like to transfer all of my save data from the 5.50 console to the 5.05 one as i have a number of games fully completed. Is it possible to transfer all of my saves, and potentially any downloaded games? If so, how. If not, why?

Thanks in advance for your help and support!