I'm aware of that, but aggi seems to be talking about electoral reform for general elections, not party leadership. I understand PR is being pushed for as something to discuss during the conference, but I've not been able to find anything from the leadership on it.
https://www.theguardian.com/politics/2021/sep/21/major-row-brewing-over-plans-to-change-way-labour-elects-party-leader