When a new version of an API is released it's quite common for parts of it to become deprecated. It could be a class, method, interface, or anything that has been found to be no longer needed. It might be the case that the deprecated part leads to unsafe code or simply that there is now a better approach. Either way, once something has been tagged as deprecated programmers are encouraged not to use it. There is no longer a guarantee that it will exist in a future version.
Using something that has been deprecated will not stop the code from compiling, but there will be warnings from the compiler complaining that you should be using something else. In fact some IDEs, like Netbeans, actively discourage the use of deprecated elements by showing them with a line through them.