To do a cross-Android version update from Android 7 to Android 8, you need to update to the last Android 7 version before the first Android 8. Take ZE520KL for example,
WW-14.2020.1712.85>manual update>WW-15.0410.1712.31>auto update to your preferred Android 8 version
Comments
Hi gr1042682
Thank you for your asking. Are you trying to upgrade from Android 7 to Android 8?
1. Is your model ZE520KL or ZE552KL?
Model Name: Settings>System>About phone
Refer to the link below to check the model name by model no. in the link
https://www.asus.com/support/FAQ/1014441/
2. Your current firmware version
Settings>System>About Phone>Software information
To do a cross-Android version update from Android 7 to Android 8, you need to update to the last Android 7 version before the first Android 8. Take ZE520KL for example,
WW-14.2020.1712.85>manual update>WW-15.0410.1712.31>auto update to your preferred Android 8 version
# Manual update guide
https://www.asus.com/support/FAQ/1009748/
# ZE520KL Firmware Spot
https://www.asus.com/Phone/ZenFone-3-ZE520KL/HelpDesk_BIOS/