Hi, yes you can!
It's best if the new servers have roughly the same performance (at least similar amount of RAM) so that if the most powerful host fails, others have enough performance to accomodate all VMs from the failed host.
And also - make sure the new hosts have CPUs from the same family as the old ones. Then before adding new hosts to the cluster, set up enhanced vMotion compatibility (EVC) on the cluster. This arrangement allows you to perform vMotion across old and new hosts. Failing to do this could cause problems in the future, eg. when putting a host in maintenance mode. Remember, you need to set the EVC baseline before you add the new hosts 🙂
Best regards, Pavel
