In this scenario, needs to be upgraded.

Chain of events:

One of the systems is designated master and updated with the most recent versions of all the configurations, typically by importing a fresh export made from the production.
The master is upgraded by following the upgrade instructions in the Installation Instructions.
When the system has been upgraded successfully, the configurations are exported to the local working copy using the vcexport command.
The resulting xml files are compared with the ones in the Version Control System.
Any changes to the files will be the result of a configuration upgrade or changes triggered by the upgrade.
The new exported configurations are checked in to the Version Control System.
The rest of the systems are upgraded.
The latest versions of the configurations are checked out from the Version Control System and imported into the systems.

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