It did upgrade the old VPN Policy Routing to pbr-iptables just fine, the luci app was not installed though.
I managed to install it with opkg install luci-app-pbr luci-i18n-pbr-en --nodeps and it seems to be working. However the updater now wants to uninstall those two packages again. Is there a way to make it ignore these packages?
It is not possible to just install them as they seem to depend on pbr and with that on firewall4 and some nft packages.