confused go for ps4 5.07 or lower

Hi Guys

I just got days of play console which is on 5.07 but been worried due to no downloaded 5.07 firmware available in case i had issues with HDD.

I am able to get a slim version which is below 5.07 so confused if i should swap it for that?

Will there be games in future that will work on 5.07 and not 5.05?

Any suggestions?

Thanks