Unification made upkeep significantly easier and enabled several fixes to be implemented that could not be done with discrete patches.
After the release of the Legendary Edition of the game which included all three add-ons, these separate mods were discontinued in favor of the unified USLEEP mod which required all three of the aforementioned add-ons and was first formally released on November 7, 2015. The Unofficial Patch was originally packaged in a series of discrete mods specific to the aforementioned game components and designed to work in concert: Unofficial Skyrim Patch, Unofficial Dawnguard Patch, and Unofficial Dragonborn Patch.
Likewise the USLEEP mod is incompatible with the Special Edition of the game. The USSEP is incompatible with the Legendary Edition of the game the older Unofficial Skyrim Legendary Edition Patch ( USLEEP or USLEP) mod should be used for that edition.
These fixes range in importance from dialogue typos to quest-breaking bugs to reducing save file bloat, and cover both the vanilla game and the official Dawnguard, Hearthfire, and Dragonborn add-ons. The Unofficial Skyrim Special Edition Patch ( USSEP) is a major mod started by Quarn and Kivan, and currently coordinated by Arthmoor, that fixes numerous bugs left over even after the latest official patch is applied to Skyrim.
