If you are doing parallel upgrade from SCOM 2007 R2 to SCOM 2012 that means you have two SCOM environments. In such situation it will be difficult for support teams to work with two SCOM consoles. To ease that process Kelverion create a runbook from Orchestrator 2012 that will allow you to forward alerts from SCOM 2007 R2 to SCOM 2012. That way you can consolidate all alerts at one place. The best about this runbook is that Kelverion is offering it for free download. Download it from here.