You cant. At most you can set it to only update when you start it but thats the latest.
But some games offer older builds on their BETA branch.
To look if your game offers that, right click it in the library, choose "Properties" and then the "BETAS" tab.
Look if the BETA PARTICIPATION dropdown menu on the right offers older game builds.
That would look like this example from Stellaris:
https://prnt.sc/Eq8hELOuVC78

If you switch to a older gamebuild the game will no longer automatically update and will stay permanently on that game version unless you manually leave the BETA build of the game.
Sadly not many game developers offer this.

You could use Tharon's tool 'Please Do Not Update Me':
https://steamhost.cn/steamcommunity_com/groups/for_a_better_steam_client/discussions/1/3417685271692378840/

im not so sure you understand the old box games issue, with games that was not update even then patch was made, ppl still complain over game is buggy, thats why its doing a check version now and fix games, ( and why you dont have that option as a choise.)

why should a game devs hear on BS from ppl then its fixed already,
be happy someone tell you this, im sure you will not have all the issue that box games cause , im sure next gen ppl have forgot the bigger the games is the more bugs is there, and no they cant test open wolrd games, it will take 20 years to release a game then, the combination of possibilites with things that noone else thougth off i think win in lotto is faster then check all possibilites.

and box games with other software protection media issue and scrates and new blueray media reader got issue with read old disk and list is so long of issue you will still runing around and ask wtf i pay for this, im sure all get alaugh out of this post , but ask old gamers here we have seen all BS from past ways that cause greef with patches and version and you name it, No one is laughing anymore.

if they did that here have 20 diffrent upgrade and build version nr + dlc + patch yp to new version then upgrade again, and then event and then pastch again,

are you done laughing now, thats how complicate it once was, some games had over 10 patch and upgrade patchg to other version it was a nighmare for new pc owners.

so NO you will not have option and never will have them. game devs will not explan all this crap then games had so many expansion and fixes over years.

and be happy someone bother with a reply like this, you have actual no choise, its like the do you agree to this or not or game will not work. ( online game do this already )

and game devs will not waste time on diffrent player diffrent version of a game support,
so you can forget about its a single player game so why not.

this is why i tell you dont have a choise, they could say update your game or we cant help you, aient that same as have nice day, byebye.

as i said we have seen all BS here. over 40 years of gaming.

This an old thread I know but I have an issue with update 153015 I am an 85 + gamer and the figures/characters/people/animals etc. in the new update have been miniaturised and are a big strain on my eyesight , I have been playing AOII for many years
The miniaturisation is why I got a refund on the latest AO mythology.

This thread was quite old before the recent post, so we're locking it to prevent confusion.