Hi Maxime,
thank you for your question. Unfortunately, there is no filtering implemented on the upgrade_info field in the Urban API.
To explore filters available for different operations and fields, you can use the docs tab in the graphiql interface, available at https://urban-api.arcgis.com/graphql.
For example, the following filters (in purple) are available for the UrbanDesignDatabases query:
Sometimes, filters are also implemented on the field level, for example you can filter thumbnail field by the size.
However, if you search for the upgradeInfo field, you can see that no filters are available.
For your current issue, I would suggest filtering the returned query response and finding the GlobalIds of the urbanDesignDatabases that require the upgrade.
Please let me know if you have any further questions.