Updates to game executable has caused some amount of confusion among players. We have been replying to posts in several forums. I ended up typing replies to Minions as well.
It was pointed out for me that not all Minions are in Discord, or visit community threads in Steam. I saw it best to store these instructions here as well.
How to delay Fallout 4 update in Steam
This method requires Fallout 4 Script Extender (F4SE). Most people who want to delay game updates are the ones using F4SE, due to version check being incompatible with game runtime changes. Note that change should be in place before update comes online. If you want to delay future updates until F4SE + plugins catches up with them, then best time to do this is right now.
Steam Library view: right click Fallout 4.
Properties > Updates > Update
Change to: Only update this game when I launch it.
Launching the game through F4SE launcher does not cause the update.
How to backup Fallout4 executable
This should be done, in case Steam forces the update anyway.
Most simple method is to copy the file in your ...SteamApps\common\Fallout 4 folder. Then paste it to a folder outside of this folder.
Other option is to use following F4SE plugin from CDante, which will automatically backup the executable to set folder. See instructions from the page.
Fallout4.exe Auto-Backup by CDante https://www.nexusmods.com/fallout4/mods/26956