The upgrade uses the upgradeToAndCall method (the selector is 0x4f1ef286) and is combined with the DOMAIN_SEPARATOR call (the selector is 0x3644e515). The method call is only used in tandem with Tenderly to check that the domain separator is not being changed from the old implementation to the new one during the upgrade.
Applied with the upgradeTo call (the selector is 0x3659cfe6).
Note: the zkBobPool implementation contract introduces new events which are emitted when the pool parameters are being setup/changed. The next three actions are required to emit the events for the current set of parameters. These events can be displayed later through an analytics dashboard.