This has been brewing for quite a while now.
There has been a serious lack of support from Nexon for KMST and they've promised better support for a very long time now but that hasn't come and thus KMST will be closing off on the 31st with a new test server to open in the future. So no, it won't be going away permanently but it will be gone until Nexon can get its act together.
10/31(금) 2014년 2차 테스트 및 테스피아 서비스 종료 안내
What that notice is saying is that in order to make way for the new test server, the current term and test server service will end on the 31st. Both game and website will be unavailable with more information about the upcoming test server to come soon.
(Must have test server account to access)