Skyrim Update 1.6.640 [ Limited Time ]

Use Unofficial Skyrim Special Edition Downgrade Patcher from Nexus:

Warning: After downgrading, set appmanifest_489830.acf (Steam's Skyrim manifest) to Read Only and change its "StateFlags" to "4" (Update paused).

For the average player who just launches Skyrim via Steam, 1.6.640 was invisible. For the modder, it was a seismic event. Here is why:

If you stay on 1.6.640, go to skse.silverlock.org and download SKSE64 build 2.2.3 (specifically for runtime 1.6.640).

If you have already been updated and your mod list is broken, do this:

For the average player launching Skyrim: Anniversary Edition or Special Edition on PC (Steam) or console, the most visible changes included:

For console players, 1.6.640 was almost entirely positive.