The contract does not guarantee GPON or XGS-PON. They have a tool to help you figure out what you have, but they can legally change it when they're upgrading their network.
The only guarantee is that they'll give you a new provider owned ONT and router during the upgrade. But that's not very useful if you want to keep running your own equipment.
The only guarantee is that they'll give you a new provider owned ONT and router during the upgrade. But that's not very useful if you want to keep running your own equipment.