Is QTP3 Compatible with The Unofficial Oblivion Patch 2.1, 2.0, or 1.7?
It is compatible with all of these, but you need to either install UOP 1.7, 2.0, or 2.1 before you install QTP3 or (if you already installed QTP3 and then later install one of the UOP versions) install the UOP 2.1 Compatibility Patch for QTP3 (described near the top of this page) after installing both QTP3 and UOP. The UOP 1.61 mesh fixes are included in QTP3 wherever they needed to be altered for parallaxing, so if you install any UOP version afterward then it will overwrite some meshes and some textures in QTP3 — resulting in the loss of parallaxing on those UOP-fixed meshes, as well as mismatched normal maps if you use UOP 2.1.