Server replacement

Hi,
We are going to change our zimbra server in our company.
So we decided to install a new Zimbra in our new server.
The old server an the new server are going to run in same time during one month.
We need to test several things about the new installation and all the changes we need to do.
So the question is, can we use the same licence to use ZxBakup on new server and old server ? (Backup on old server and restore on new server only).