Question regarding installing ROMs after upgrading to new stock JB

[gulci]

I'm a little rusty in my understanding of how the stock OS works in regards to other ROMs I install. I'm pretty sure that once I've upgraded to JB in stock, I can't install ICS ROMs anymore... however, can I install Jellybean ROMs designed for ICS but are JB? I'm interested in this ROM but I'm not sure if it will work with the new JB kernel that I have because I upgraded.

I would love to understand this, could somebody please enlighten me? Thanks!!

 

[GigaJake]

Avatar ROM will work on your JB device, I can attest to that personally. All ROM builds now are Kexec, meaning they run off of a custom kernel. Both ICS and JB users can use Kexec builds.
CM10.1, AOKP, Liquid, Avatar all use kexec, and unless a ROM specifically states that they run off of a specific kernel, I would assume they're Kexec at this point.

 

[gulci]

Thank you very much!! I've seen the term Kexec being used but I completely missed that this was in fact a custom kernel. That makes complete sense, thank you so much for answering my question.