The Undermountain has gotten a chunk of new content, as have the Temple of Mallach and several of the neglected NPCs from the early game!

0.4.5 Patch Notes:

• If you’ve built the Temple of Mallach and have romanced Kas past the Winter City, there is a new event that may trigger at the temple…
  
• New NPC in the Mallachite Temple: Rune!
  
• Atugia has a BUNCH of new sex scenes and talks!
  
• You can now give Ryn a dildo or permission to seek out your companions for sexual relief.
  
• New Undermountain enemy encounter: Kobolds!
  
• New Undermountain enemy encounter: Minotaur Miners!
  
• Senja now has much-expanded interactions if you chose to give her a smooch before!
  
• Miko’s old scenes now fully account for her pregnancy.
  
• There’s a new jotun/lupine Cboy in the Rift, who you can push towards different sexual arrangements.
  
• The Wraith Chimera has a new loss scene
  
• There’s a new scene for walking in on Liaden and Azzy, complete with a new CG.
  
• The hornets in the Old Forest are now switched out with an updated version of the encounter after finishing the hive dungeon.
  
• You can now tell the elf boi in the forest to go away forever.
  
• New TFs: Deer, Catmorphs, Siorcanna
  
• Salamander TF now gives cock types. New hairstyles for dreads and afros!
  
• New Busts: Rune, Kobold headshots, Elementals, new Temple friend. Etheryn's got a new bust series by DCL!
  
• New CGs: Brint x Atugia by Moira, and Lyric gettin’ fucked by DCL, and another for Lady Evergreen’s sex menu (Done by Mr. Pink and Waru-Geli)!