Hi
eros.palado.21Thank you for your asking. Please refer to the upgrade steps as below
Update the device to the latest Android 7 version WW-14.0400.1808.206 >Download the first Android 8 version WW-15.0400.1809.405 file into the root directory, aka the outermost place, of the internal storage>Reboot>Tap the system update notification
ZenFone 4 Selfie (ZD553KL)|Phones|ASUS GlobalIf you still can not upgrade the device, please provide me your current firmware version.
Settings>System>About Phone>Software information