The shutdown announcement from Gameforge should be happening soon enough
I don't think GF has any intentions on shutting down the game as of right now, as I believe Tera belongs to their most profitable products. Have a look at GF's portfolio and you will see loads of other games (I don't want to mention names here..), which are in an even worse condition (low playerbase, dead servers, rarely updates, etc) than Tera is right now. GF knows how to run games at the lowest cost possible and where to save money (customer service, community management, etc.), that's how they have managed to keep the supposedly unprofitable games profitable. With the acquisition of the NA and RU servers, I believe a shutdown in the near future has become even more unlikely, and I doubt Krafton is charging them high license fees...