When migrating from Denodo 6.0 to 7.0, the VQL should be exported from 6.0 and imported directly into your 7.0 installation. Therefore, you only need to install Denodo 7.0 on your new servers.
Before exporting the VQL from your 6.0 installation, you should make sure to:
1. Install the latest Denodo Platform update on the 6.0 installation
2. Set the migration properties described in the migration guide.
For more information on the migration, I suggest that you read through the [Migration Guide](https://community.denodo.com/docs/html/browse/7.0/platform/migration/index).
Hope this helps!