The current v5 firmware is BT v5.29.107.19 and that is the one BT are currently updating to V6.
I have just bought a dual SSID from Ebay (£2.20) and it has come with firmware 5.29.117.6 installed which appears to be a later version.
It is up an running perfectly but would I be better downgrading the software to the BT v5.29.107.12 recovery firmware?
In my present software there is no tick box on the management page to permit me to disallow Inbound and Outbound Control Remote Management.