Why am I only finding out about this now… I didn’t even read the patch notes, outside of balance changes.
But I’m actually happy about these things, as it gives me something to do & earn. Now to waiting for this damn rare spawn to appear tomorrow on my next run into Scholmance >_>
But now off to Zul’Gurub and then the other places to try and get the old versions unlocked 
I’ll link all the guides below for people who want to know as well.
Zul’Gurub: https://www.sportskeeda.com/mmo/how-unlock-secrets-zul-gurub-world-warcraft
Naxx (including Scholomance): https://www.wowhead.com/news/unlock-secrets-within-naxxramas-how-to-start-looking-for-old-naxxramas-gear-333989
I believe are some others and I’m going to try and find them and link them above, but having to deal with a hyperactive child, so will update this asap 