The only changes here are to the lower left corner of the map, the "Great Stair" section. The number of ways into the section (at least from this level) has been chopped down, and a large stairway has been added.
There are four major sections to this level. Starting at top left and going clockwise, they are "Thieves Chambers", "The Dust & The Damp", "The Tubs", and "The Great Stair". I haven't gotten much past that for details, but I do have some general concepts.
"Thieves Chambers", obviously, is under the control of a minor band of thieves. Guild is probably too high of an aspiration for them. They access their section via the ladder, and make sure to leave the door to the well-room (1-12) closed and locked. They've had some bad experiences, so as a general rule stay to rooms 1-8 through 1-15. They know about the secret door to room 1-1, but none of the rest, and leave the door to room 1-7 locked.
"The Dust and the Damp" lacks any kind of organized control. Rats and one or two mindless sort of monsters are the likely threats here. A giant raccoon has established a lair in 1-33, coming and going via the stream (which flows into the dungeon at this point).
"The Tubs" are also undetermined. Water-based monsters are likely. At least one of the pools (the smallest one) possesses a magical "heating element" that warms the water, a la Roman baths (a hypocaust would be neat, but a bugger to map unless I switch to a 1-square = 1 foot scale, and it would then be a bugger for the adventurers. Unless they used reduce person...) Rooms 1-47 & 1-48 will have something going on. Passage 1-49 is accessed by climbing the wall from the waterfall to the passage opening; a short distance, but not something the PCs are going to do easily. This will be generally true of aerie levels.
"The Great Stair" is probably a goblin-held section. Their warren spans several levels. The great stair itself drops to level 3.