In order to migrate your legacy data from Mimecast into Jatheon we will need all your historical emails exported from Mimecast.

As Mimecast is providing 2 types of exports: into an extended and standard format, it is really important to note that Jatheon needs the Standard format (extended format includes badly formatted envelope emails, not in Microsoft format, unusable for Jatheon and other archiving systems), while the standard format means that the output is standard raw EML files. Note that by design, in the Standard export done by Mimecast BCC info is not included, and therefore Jatheon will not be able to index the BCC field.