The Borderlands 4 patch notes have been released alongside the Horrors of Kairos Halloween event, addressing unintended interactions that caused excessive damage scaling and boss-melting builds. A change that hindered players' ability to speed-farm bosses for loot was confirmed as unintentional and will be reverted. The vendor trick for resetting character skill cooldowns has been disrupted but will be reinstated. Several character abilities, such as Vex's Bloodletter passive and Harlowe's Neutron Capture, have been adjusted, with some effects being significantly reduced. The cost of specialization respects has decreased from 5,000 Eridium to 1,500, and improvements have been made to the Lost Loot machine's logic. New Shift codes for Borderlands 4 are available for players to collect Golden Keys.