Fortnite Battle Royale for Mobile and its network technical difficulty question.

Epic just announce here -
I have some question regarding network technical difficulty.

  1. Mobile bandwidth is expensive.
    I don’t know about mobile bandwidth cost in the west.
    Consider the gameplay, It forces a lot of player within clamping area and that can flush mobile bandwidth.
    To iterate quickly, Epic need a better network compression workflow.
    Currently, we need to mix compression algorithm with RPC code. has shown how to do this with IDL.
    Am I missing best practice with network compression in Unreal Engine?

  2. Mobile client cannot simultaneously get global update through store.
    This mean if we change synchronization protocol, such as modifying RPC call or replicated state,
    the old client cannot play and need to wait until update become available in their region.
    Is there anything I need to know how to support older protocol within Unreal Engine?