Is it possible to run a mix of different EAP (EAP6 and EAP7) versions within the same domain?

Issue

• Is it possible to run EAP in domain mode where the different hosts have a different version?
• Can I run EAP servers with different versions in the same cluster?
• Are different EAP versions compatible and can run in the same domain?
• We are running EAP 6 in domain mode and want to use EAP 7 management features without upgrading the entire domain.
• We are running EAP 6 in domain mode and want to add EAP 7 hosts.