Patch 1.12 (11 January 2016)
Hearts of Stone

Fixes issue whereby achievement titled Wild Rose Dethorned could not be completed.
Fixes interaction on pickaxe in quest titled Enchanting: Quality Has Its Price.
Fixes issue (in majority of contexts) whereby not all diagrams could be collected in quest titled From Ofier's Distant Shores.
Fixes rare issue whereby some players were prevented from spreading smoke throughout all rooms in crypt during quest titled Dead Man's Party.
Fixes issue whereby book merchant named Marcus T.K. Hodgson failed to appear in market square in Novigrad.
Fixes rare issue whereby some Knights of the Flaming Rose in quest titled Open Sesame! in Hearts of Stone expansion could not be killed.
Introduces a number of improvements to general game performance.
Fixes issue whereby treasure hunt titled The Drakenborg Redemption remained in Journal despite completion of all objectives.
Fixes issue whereby swapping of enchanted gear within Inventory granted permanent bonuses to statistics.
Fixes issue whereby treasure hunt titled The Royal Air Force remained in Journal despite completion of all objectives.
Fixes issue whereby players could not eavesdrop on guards during quest titled Witcher Seasonings in Hearts of Stone expansion.
Fixes issue whereby some players could not talk to Shani at certain juncture of quest titled Dead Man's Party in Hearts of Stone expansion.
Introduces a series of minor difficulty balance tweaks at all difficulty levels in Hearts of Stone expansion.
Fixes rare issue whereby inebriation effect would persist on screen after quest titled Dead Man's Party in Hearts of Stone expansion.
Fixes issue whereby phase titled Enchanting: Start-up Costs would remain in Journal after Enchanter was paid relevant amount.
Fixes incorrect Stamina bonus granted for Caparison of Lament in New Game + mode.
Fixes incorrect mesh appearing on Viper School swords in New Game + mode.

DLC

Fixes previously unlootable container within Kaer Morhen watchtower during quest titled Scavenger Hunt: Wolf School Gear.
Fixes rare issue whereby a doll could not be picked up in quest titled Where the Cat and Wolf Play.
Fixes specific user's issue with werewolf in quest titled Contract: Skellige's Most Wanted.

Main Game
Gameplay

Fixes issue whereby some toxic gas clouds failed to poison or deal damage to player character.
Fixes issue whereby scabbard meshes were missing from witchers other than Geralt.
Fixes rare issue whereby attacks performed near friendly NPCs resulted in unintended regeneration of Stamina.
Fixes exploit involving Alchemy skill titled Tissue Transmutation.
Fixes issue whereby quickslots could disappear if game difficulty level was changed during combat.
Fixes exploit involving Superior White Raffard's Decoction and skill named Delayed Recovery.
Fixes rare issue whereby skill named Flood of Anger incorrectly enabled Signs Tree and enhanced Sign Intensity permanently.
Introduces fix whereby special bonus granted by Superior Blizzard will take effect only when slow-motion is triggered.
Fixes a number of issues affecting potion called Chort decoction.
Fixes rare issue whereby some mini-bosses could become immortal under certain circumstances.
Fixes misleading message displayed when players attempted to cast Signs in combat, while enveloped by a cloud resulting from the detonation of a Dimeritium Bomb.

GUI

Fixes issue whereby items in merchants' stores could not be compared to currently equipped items.
Fixes exploit whereby some items (runes, glyphs) could be upgraded infinitely.
Introduces UI enhancement whereby herb name is now displayed above available interaction.