Check latest game server version

[P4sca1]

I am writing an update script which should check the latest game server version and update if necessary.
Is there any http endpoint for checking the version?
The only thing I found out is that I can use steam web api http://api.steampowered.com/ISteamUserStats/GetSchemaForGame/v2/?key=XXXXXXXXXXXXXXXXX&appid=4000
to get a gameVersion attribute for Garry's Mod but not for the dedicated server. Also it seems like the gameVersion is not incremented for hot fixes or similar things for some games.
Does anybody know a better approach? Or is it enough to just check for a garrys mod update via the gameVersion attribute?
A perfect solution would be to have a http api similar to steamcmd's app_info_print 4020 (depots.branches.public.buildid), but that information seems to be hidden from steam web api.

[Devix]

why you don't use steamCMD ? launch a app_update 4020 and it will be update gmod server if it's needed

[Geferon]

He doesn't want to update the server if needed, he wants to check if there is an update available, probably to fetch a method or maybe inform the clients that are on the server, or whatever other reason he needs.

I actually wanted to know this as well some time ago.

[Devix]

so when server need to be updated

[P4sca1]

I don't want to directly update the server, I want to know if there is an update before going into the process of updating.
As @Geferon pointed out it is useful for doing things like notifying players, and other things.
In my case I want to inform server admins that there is an update and they should restart the server as soon as possible to apply the update.

[YunoGasaii]

The only thing I know is app update print.

you could try getting the date of the current update build and cache it and compare it to your last update that happened.