The CellObjectDestroyer base abstract class has been renamed to ChunkDestroyer. Any custom Cell Object Destroyers you have created will need to be recreated using ChunkDestroyer as the class they derive from. You can find this class within the DeepSpaceLabs.SAM namespace.
While the name of this method has changed, it still takes in a game object and so should function in much the same way. The method now also includes a ChunkStreamer.ChunkStreamerUser parameter, which can give you access to useful information about the LOD Group that the chunk belongs to.
This is a new method that you will need to implement; it should carry out the destruction of all chunks on the list of input World Cells, however aside from that, all details are left up to you.
The method includes the Memory Freeing Strategy set in the Chunk Streamer that is calling the method, however it is up to you whether you want to respect that strategy.
A ChunkStreamer.ChunkStreamerUser parameter is also included, which can give you access to useful information about the LOD Group that the World Cells belongs to.
If you need assistance with your Custom Chunk Destroyer class, please take a look at the Custom Destroyers Section within the Chunk Destroyers Chapter.