Skyrim Ussep 1.5.97 [verified] -

While the game has evolved through numerous updates, version holds specific significance. Released in late 2021, this was the final version of the game before the implementation of the "Anniversary Edition" content and the update to runtime version 1.6.x. Consequently, 1.5.97 became the final "stable" environment for modders who did not wish to integrate the Creation Club content managed by the new Bethesda.net overlay. This paper explores the symbiotic relationship between USSEP and this specific executable version.

Users maintaining the "pre-anniversary" 1.5.97 version of Skyrim Special Edition for mod stability often require the archived USSEP version 4.2.5b, as the latest patches are incompatible. For continued stability with complex load orders, veterans recommend using the "Best of Both Worlds" Skyrim Downgrade Patcher to maintain 1.5.97 compatibility while utilizing essential SKSE plugins and .NET Script Framework. You can find more details and the patcher on Nexus Mods. skyrim ussep 1.5.97

Therefore, refers to the legacy build of the patch—typically version 4.2.5b or earlier (before the AE conversion). While the game has evolved through numerous updates,