Most popular mods that require SKSE are built for, or have a dedicated version for, 1.6.640.
Some mods have proven more problematic on 1.6.640:
The community’s "downgrade patcher" (by user Halgari) rose to prominence specifically to revert newer versions to 16640, underscoring its status as the verified fallback. skyrim special edition 16640 verified
: Later patches (1.6.1130+) merged the mod menu and Creation Club into a unified marketplace, updating the internal compiler and permanently breaking older .dll code dependencies.
Released in late 2019 alongside the "Creation Club" updates, version 1.6.640 (commonly referred to as 16640) is not the newest iteration of SSE—yet it remains the most verified , trusted, and widely adopted build among PC modders. While later updates (1.6.1130 and beyond) introduced UI overhauls, paid modding friction, and script extender incompatibilities, 16640 sits in a sweet spot: stable, fully compatible with SKSE64, and backed by thousands of community-tested mods. Most popular mods that require SKSE are built
For users who want to stay on 1.6.640 but use mods with newer plugin versions, (Backported Extended ESL Support) is invaluable. It allows plugins from 1.6.x versions to run on older game versions, effectively bridging the compatibility gap.
✅ You want to use most modern Wabbajack modlists (many are locked to 1.6.640) ✅ You want a stable, well-supported modding environment with broad mod compatibility ✅ You want the four free CC items (Survival, Fishing, Rare Curios, Saints & Seducers) ✅ You don't want to deal with Bethesda's new Creations menu and paid mods ✅ Your desired SKSE-based mods have been updated for 1.6.640 Released in late 2019 alongside the "Creation Club"
Released on September 20, 2022, this patch focused on several quality-of-life fixes for the Anniversary Edition content: Skyrim:Special Edition Patch - UESP Wiki