Hmm: 5.05 was the fw before 5.50, im sure sony allows the one firmware revision before the latest to connect online to do stuff without forcing an update.
Hence today 5.53 is out 5.50 will work online, but anything lower will now no longer work.
I thought this too as I used to freely update my games on PS3 thanks to constant Cfw updates to accomodate patches requirements. Im pretty sure this is not possible on PS4. Im sure it was confirmed shortly after 4.05 dropped public.
Can anyone re-confirm this?
Also: The updates require higher fw versions and would mean uninstalling the entire game to reinstall the base game if it did infact work...