You can migrate data from more than one source hierarchy, and the source hierarchies do not need to be the same version as each other. This means you can migrate from one or more Configuration Manager 2007 hierarchies, one or more System Center 2012 Configuration Manager hierarchies, and from one or more hierarchies that each run a different version of Configuration Manager. However, you can only migrate from one hierarchy at a time.

You can migrate the hierarchies in any order. However, you cannot migrate data from multiple hierarchies that use the same SITE code. If you try to migrate data from a site that USES the same site code as a migrated site, or that uses the same site code as a site in your destination hierarchy, this CORRUPTS the data in the System Center 2012 Configuration Manager database.

You can migrate data from more than one source hierarchy, and the source hierarchies do not need to be the same version as each other. This means you can migrate from one or more Configuration Manager 2007 hierarchies, one or more System Center 2012 Configuration Manager hierarchies, and from one or more hierarchies that each run a different version of Configuration Manager. However, you can only migrate from one hierarchy at a time.

You can migrate the hierarchies in any order. However, you cannot migrate data from multiple hierarchies that use the same site code. If you try to migrate data from a site that uses the same site code as a migrated site, or that uses the same site code as a site in your destination hierarchy, this corrupts the data in the System Center 2012 Configuration Manager database.