drop-in migration zarafa 7.1 to current kopano version

We had a customer which uses currently zarafa 7.1.14 and after long time he agreed to change to the newest version of kopano. Which is the best way to migrate from this older zarafa version to the current kopano version? because he ad a large public folder (many attachments) a drop-in migration i think is the best way.

Is a direct drop-in still possible? like copy the attachment folder and the mysql database to the new server, which is up2date and had the newest config, or is their a step between needed like migrate zf 7.1 to 7.2 and then to kopano? (because i don’t find any zarafa downloads anymore after shutdown of the portal.zarafa.com)