z2 23.4.A.0.580

Hi Guys

Question i have a new z2 with the 580 Firmware, and now i look for Solutions how i can install root/costum Rom.

is possible to root 580 Firmware ? or downgrade ? when YES How?
after root can i install a costum Firmware over CWM or somthing (Bootloader LOCKED) ?

pls help me (expirience 5 Years Samsung, but first time with sony)

regards
CK