Looking for guidance topic

I am fairly familiar with rooting and such, but I am currently lost. I just received my hdx (thor) and have it rooted with a custom recovery and a stock backup. But, my question is, do I need to be on certain versions for certain custom roms? I'm currently on 13.3.1.0. Would I need to download/install a more recent version before I can began flashing?

Thanks in advance