So some quick background.
For those not familiar with the planned "Guild Conquest" mechanic that was supposed to be introduced in Q3 2025 and you can read about it here and here. That game mechanic was "paused" until at least 2027 for good reason and we should all be thankful for that. The problem is Inno wanted to make GB's great again and a large part of how that was going to happen involved the introduction of Guild Conquests and GB's that provided bonus or effects for that mechanic.
The GB's and reward/quest system of the new age also relied on the GB update to be in place at launch so that was delayed as well.
Guild Conquest -- GB update -- New age mismanagement are all linked.
So once Guild Conquest was officially taken off the table the GB upgrade was going to proceed.
You can read about what it was going to be
here. The reason we don't have it is because of the huge backlash from the community. That backlash stemmed from how they planned to handle the bronze/tier one level of the new tier system.