Originally Posted by westi2002

The additional seats become available somewhere in the night before T-72, that's indeed the standard. The pending payment you will see at check-in, there will be no option to change the seat or to buy an upgrade.

Just arrived from outbound, see screenshot for inbound, no possibility to click on seat assignment to open seat map. Screen on the Andriod app is similar, no option to click on the seat. So maybe only iOS version allows to change seats?