We can't talk Notes email migration without mentioning coexistence. If your migration project requires directory, calendar and free/busy coexistence, then we encourage you to try Coexistence Manager for Notes in your own environment.
You can download the free trial download at any time at this site location: https://software.dell.com/register/55142.
Feel free to reply to this thread at any time with questions or you can also contact our Technical Support team during your trial period here: https://support.software.dell.com/.