Is it possible?

[RayJenkins]

Can I perform an upgrade from CentOS 6.1 to 7.x without disrupting EFA functionality? Currently, I have EFA-3.0.2.6 operating on CentOS 6.1, which has reached its end-of-life. The virtual machine performs well with 2GB RAM under low traffic conditions, and I wish to avoid upgrading to version 4.x due to its increased RAM/CPU demands and the limited resources of the host VM. Additionally, I want to prevent the need for reconfiguring custom settings from scratch. However, I also recognize the importance of moving away from an unsupported operating system.

[pdwalker]

I would seriously consider making a new vm and then do a migration from the old 3.x system to the 4.x system.

Centos never supported inplace upgrades between major versions and I would be very hesitant to even attempt it given how many ways it could go wrong.

Maybe this post will help you through the process: viewtopic.php?f=5&t=4325