It means the Battlefield 4 CTE service will stop operating on March 6.
It means the Battlefield 4 CTE service will stop operating on March 6.
That means they plan to stop all online services, including Battlefield 4, and there’s no indication of it happening right now.
This indicates they're no longer producing fresh material. The output will start to feel outdated, similar to popular releases that have already been released.
The CTE stands for Community Test Environment. It's a collection of servers used by developers to trial updates before releasing them. Turning those off means DICE thinks Battlefield 4 is finished for now. EA stopped official support for Battlefield 2 and Battlefield 2142 about two years ago, so you probably won't need to worry about BF4 for a while.