IP address may change as well for PPPoE connection. It depends on your ISP, see if they provide you a static IP address.

before update do you have the gateway option? if so, you may downgrade. it seems they remove it

very strange mate. you should contact tplink support to dig it out.

Yes I mean uninstall the utility. Then download it from tplink website, run the program again. Once installed, it will show on the desktop. That utility is not necessary. You can use the windows...

There's gateway option under DHCP settings

It's empty cause it finds nothing worth recording I think. You can disconnect your devices from wifi, reconnect to see if any log comes out. Sometimes the log is not that important.