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The migrated data will overwrite the existing. There is a lookUp for users and groups as well.The user and group references handled by the Configuration Manager

User Settings

The user settings of the users who exists in both instance will be overwritten with the migrated data.

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Group User, Version, Component, Issue Type, Priority, Projects, Assignee, Reporter, Status, Resolution references will all be also checked if they exist in the new environment as wellby the Configuration Manager.

Not Migrated Data

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User History won’t be migrated

deleteConfiguration

This function will be called if an app is not included in the snapshot. Every settings will be set to default.