When migrating from vCenter Server version 6.0 or earlier, you must prepare your environment before migrating the Content Library to prevent pre-check errors.
All ESXi hosts from the source vCenter Server inventory must be supported by the destination vCenter Server 6.5.
The source vCenter Server Content Libraries must be backed by either remote file system or datastores . You cannot use libraries backed by the local file system of the vCenter Server.
All the remote file system shares used as library backings must be accessible at the time of the migration.
No subscribed libraries are using file-based subscription URI.
If you are migrating from vCenter Server 6.0 U1, no actions are necessary.
The migration will fail, if your environment does not meet the requirements..