I have a ZBT3526, and have been using GoldenOrb_2017-10-10 firmware. Have tried flashing openwrt-we3526-GO2018-8-17-upgrade.bin, but I keep getting an error message,"The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform."
When you're using a third party build you should ask that group. This forum is about the official builds found at downloads.openwrt.org.
At the command line, you can use sysupgrade -f to bypass that compatibility check and force the upgrade to flash anyway. This would brick it if the firmware you flash is truly incompatible.