Welcome to the Community,
I can't tell you whether it will work with v4.0, but it may be worth trying https://www.virtuallyghetto.com/2012/06/how-to-copy-vms-directly-between-esxi.html.
Simply copying the VMs (files) may work too, but note that previously thin provisioned virtual disks will be inflated to their full size this way.
Other options are backup/restore, export/import as OVF.
Once migrated, and prior to powering on the VMs I'd recommend that you create a snapshot. Then update VMware Tools, and finally update the VM's virtual HW version. If everything works as expected, delete the previously created snapshot.