* Sysupgrade from ar71xx to ath79 and vice versa is not officially
supported, a full manual reinstall is recommended to switch targets
for devices supported by both ar71xx and ath79
* Images for some device became too big to support a persistent
overlay, causing such models to lose configuration after a reboot.
If you experience this problem, please report the affected device
and consider downgrading to OpenWrt 18.06 or using the Image Builder
to pack a smaller custom image
* Some optional GUI packages crash with an error about missing
"cbi.lua", install the "luci-compat" package to fix these
* Any outstanding issues reported at https://bugs.openwrt.org/
