Legacy iptables rules present on the system Beryl

what does this mean under firewall in Luci for beryl?

Legacy rules detected

There are legacy iptables rules present on the system. Mixing iptables and nftables rules is discouraged and may lead to incomplete traffic filtering.

Are you using 4.2 firmware? This firmware has not been officially released yet.
I think these prompts are caused by openwrt switching from iptable to nftable.

No. It is 4.1 beta. Probably the same issue. I have to use it with the router bc the official prior version wouldn’t let me connect via repeater. I’ll ignore the warnings unless you want to give me instructions to fix this. I am concerned about my internet speed while using the router with VPN. I saw an improvement once I found where to set the MTU size but I am still concerned.