

You can also still rollback using the Steam console, app ID and manifest ID right now. The SKSE launcher doesn't need Steam to launch the game. If you don't want to go through the trouble after the update gets queued you can still always launch the game directly from the SKSE launcher in the game's directory instead of through Steam.

You need uncheck "Keep this game up to date" in the game's properties before the update is released to prevent this from happening in the first place. You need to do some dirty stuff like deleting the manifest and something else to remove the update from Steam's memory. The problem is once the update is queued Steam won't let you launch the game in offline mode until the update is completed.

Click to expand."Update on launch" has been the only option for quite some time now.
