Hi friends
After checking, ZS600KL will still provide firmware update, please stay tuned to our social media channels or visit our Asus support website.
#ZS600KL Firmware Spot_Asus Support
https://rog.asus.com/phones/rog-phone-model/helpdesk_bios/Sorry for any inconvenience it may be caused. Thank you for your continued support and patronage.