A little help, please.

I'm coming from 4.4.1 I want to flash a Lollipop ROM, I haven't flashed for very nearly 2 years. I'm obviously rooted already.

Is coming from KitKat as simple as just flashing a Lollipop ROM? I'm an SM-9005, I've got Odin 3.10 and I want to flash Resurrection-Remix-LP-v5.5.5.

I've seen that I need to backup my PIT and obviously backup my current ROM, do I need to update my baseband or radio etc?