You can copy your entire Empyrion folder out of your Steam folder and it will not get updated, plus you can play that version no problem (just start the Steam client first). See this : https://steamcommunity.com/sharedfiles/filedetails/?id=885555151
Playing on a server that is slow to update is one reason. You don't want to get locked out of the server because the base game updated and the server hasn't yet. Playing with custom config files and don't want to immediately have to edit them every single time the base game updates is another reason. You can get COQ errors otherwise, or worse, corrupt your save in extreme circumstances. The method @Kassonnade outlined is the correct steps to prevent any version from ever updating. It can't update if it isn't in the Steam folder (install location). You can run them from outside Steam as long as Steam is running and everything will work as expected still. I had probably 50+ past versions of the game all saved on my backup hard drive before I went through and cleaned them out. Basically every time there was a somewhat major update to the game I backed my game install up before updating so I could continue the old version if there were major issues (or for testing purposes). Each and every one of them was playable. Heck, I could have had all 50+ versions of the game all running at once and playing online with each one if my PC could handle it.
I would love it if Eleon released EGS on GOG.com. It would allow me to update at my leisure, rather than staying on their erratic and often spontaneous patch schedule.
I don't play on servers other than - servers I host, or official servers, and I don't modify config files. My reasoning is simple: the game is still growing and developing, and as you've noted, you can corrupt saves easily enough with these sorts of modifications. Why give myself that kind of headache at this point? But yes, making a copy of the install somewhere other than where Steam puts it does give you a fully usable copy to play with, without having to be concerned an update will change something. I blame Steam for not having a "Do Not Update" option in the game Update options.
@Kassonnade is right, he/she must be either Belgian (like me !) or 'Chti' on top : You cannot disable automatic updates on EGS by Steam. The copying of the game's folder to another location is the only key. It works 100% smooth and you even still can access the builds you suscribed to in the workshop. When a new game version is launched, try to learn if it will break current savegames. In every case, if not, update the copy of the main game folder from /steamapps Cheers ! Oufti !
If you are trying to keep the game on a certain version. Right-click on the game in your steam library, select properties. Click on the "Betas" tab. Select the version you want to roll back to.
Only works for certain versions, and I still recommend copying the folder elsewhere even after you opt into one of those old builds. The reason for that is because a couple times in the past the devs (or Steam) has suddenly removed all those old versions out of the blue and then it will force update you if that happens, potentially corrupting your saves if you don't notice right away. Will that happen again? Don't know, but I still recommend to copy the folder elsewhere just in case.
