there's some info here:
and an amendment here: Update to the Announcement of Support for upgrades from EEPC 6.1.2 - 6.2.1 to DE 7.1
but if you read the KB that issue is solved in patch 1 McAfee KnowledgeBase - Error: [0xEF000008] - Failed to load cryptographic module (when upgrading from EEPC 6.1.2, 6.1.3,…
It depends what your current sever settings/assignments are- you could do an in-place upgrade. - I've just completed an in-place earlier this year- from ePO 4.5 to 4.6.7 and 6.1.1 to 6.2.1.
But now you could go straight to 7.1 according the the KB.
If you transfer systems- you will need to recreate your user assignments- user assignments don't transfer between ePO servers.
Not yet myself upgraded to 7.1 so can't offer any more advice on that side of things.