One of the more influental versions of Citadel. It's based fairly directly off of the original Citadel 2 source (originally). It's a port to the 8086 architecture -- I remember downloading it and playing around with it. There's support for networking between nodes (though it requires a tree structure sorta like how IRC servers talk to each other, so you couldn't just hook up to anybody you wanted or loops would be created), email, etc.

Based off of Citadel-86 are: