We currently have DevTest 10.5 installed on server A.
Next month we will install DevTest 10.6 on a new server B.
For two weeks the two DevTest will be active simultaneously.
I I'd like to know if we need to get a new license or we can use the same one for both servers.
DevTest 10.6 and up
Component : CA Service Virtualization
As long as the license is not expired then yes you can use it on both systems while you are doing the migration.
NOTE: If you have a license tied to a MAC address then you will have to request a new license for the new server.