Enterprise Vault nsf import version limitations

Hello,

We have a customer using Domino Server 7.0.3, in the process of migrating to Exchange 2013.

So we will have to use the Enterprise Vault 10.0.3 version it seems, but Domino 7.0.3 seems unsupported for this scenario.

Is it possible to get the nsf files from the server, and manually import them onto the EV 10.0.3? or are there any migration paths other than;

1- Upgrading many domino servers from 7.0.3 => 8.5.3 which would take some serious time

2- Using EV 8.0 first and upgrade to EV 9.0  then to EV 10.0.3 etc..

Thanks