Puzzle of use yeelight blue message interface for Android develop

1.Can not receive the notify value of the yeelight blu.
In the agreement:


there are three Characteristics for Notify: 0xFFF4 (response delay status query), 0xFFF6 (state query response), 0xFFF9 (name query response).
I sometimes receive three response values, and sometimes I can only receive the first characteristic notify. My code is as follows:


If 0xFFF4 is set to the front, only the delay status response can be received. If 0xFFF9 is set to the first one, only the notify of the name can be received.

  1. setting the device name failed
    I used to set the device name to A and it worked. Later I have modified the name to 1, but it has been a failure. (Modification to other names is also a failure)
    Data are as follows:

    I hope to get the answer from yeelight technicians, thank you!