PS4 5.55 real downgrade tool ?

Hi guys

I saw this website :
ps4portal .net /ps4-downgrade-to-1-76-official/
where it give a downgrader tool ...
Someone tested it ?
That's really look like strange ... they say downgrade work in 6.00 ^^'

And if this tool is fake, do you know if we can downgrade 5.55 to 5.05 by other tool or way ?

Thanks