One of the things that has always stopped me from upgrading is my dislike for the current way you get to channel windows. I liked the oldschool clunky tabs on the side, a lot.
After having a disagreement with some scripts and .dlls I grabbed, none of them worked so I considered upgrading to 6.35 but what I wanted to know is can you change the way 6.35 looks to make it look exactly like 6.17?
I'd download and try myself, but dialup ¯\(°_o)/¯ so I was hoping someone would be able to tell me.

Sorry if this is in the wrong area.

Sounds like you just want to disable the treebar. You can disable that in the View menu at the top of the mIRC window.

Ah, that's the one. Thanks heaps.