Can somebody explain me what is wrong with the zombie escape server?

Hi,i need an answer .what is wrong with this server?
Yesterday i was able to play,everything worked fine,now i am getting again that message : The server you are trying to connect is running an older version then your game" ,what is happening?

Before the valve update this server was ,almost , allways full ,now I never seen more then 20 players and this is not cool,In my opinion valve update screwed up this beautiful server and if those problems won't stop I am afraid this server will be about to "die".

http://store.steampowered.com/news/4812/

Also: http://store.steampowered.com/news/4820/

Your game needs updated.

Josh,are you kidding me ? I know anything about that update,i was just asking about the server problem, it is something wrong ? Because yesterday,in fact 13 hours ago i was able to play now i am getting that long message ...the server you are trying.... ,i want an explanation about what happened with ze server.

E: omG...my game is up to date,i updated it since the valve update,i was able the whole week ,before and after the valve update.

Second edit: Ah lol, there is another valve update,i didn't know that ,i will update my game,thx for this information.