Issues about MOS and CORE on Matrix Voice

Hi, I have tried to write some code on my Matrix Voice. However, I have two issues which need to be confirmed.

First, does Matrix OS not work on Matrix OS currently, right? I followed the instruction on official site. But when I did “matrix ping”, I got “client registration fail”. When I deployed an app, I got “Unable to reach device, the application will be installed as soon as your device is available.” Someone said that MOS is under maintenance. What is the status of MOS now?

Second, since MOS does not work for me. I tried to use Matrix Core. I also followed the instruction and installed Matrix CORE in Matrix Voice successfully. In everloop (turn all LED green) example, there is an magic number 35 which is the number of LEDs in Matrix Creator. However, the example works for Matrix Voice. However, because Matrix Voice just has 18 LEDs, I changed the number from 35 to 17. Then, I ran the example, I got “Matrix Creator has 35 leds”. Is it possible to change hardware setting from Matrix Creator to Matrix Voice in Matrix Core?

Third, is there the API reference of Matrix CORE? I think that the documents of Matrix CORE on official sites by using examples as references is not enough for developers.