What's the Minimum Stream Volume on AndroidDevices and how to get it Pre SDK28

They've added in 28(P) the function

AudioManager.getStreamMinVolume(int streamType)

I've checked two phones. One returned 0 (max 15) the other one returned 1 (max 8). I assume that AndroidPhones somehow use "Steps". Setting the StreamVolume to 0 didn't work on the phone where the minVolume returned 1. Even setting the StreamVolume with

adjustStreamVolume(streamType, ADJUST_MUTE, 0) 

failed.

Are there Phones that use percentage from 0 to 100 because

public static final int ADJUST_MUTE = -100;

? And my question: How to get the minStreamVolume for a specific streamType pre Pie?

Here is the formal way to find the minimum volume of a stream type.

/**
     * Returns the minimum volume index for a particular stream.
     *
     * @param streamType The stream type whose minimum volume index is returned.
     * @return The minimum valid volume index for the stream.
     * @see #getStreamVolume(int)
     * @hide
     */
    public int getStreamMinVolume(int streamType) {
        IAudioService service = getService();
        try {
            return service.getStreamMinVolume(streamType);
        } catch (RemoteException e) {
            Log.e(TAG, "Dead object in getStreamMinVolume", e);
            return 0;
        }
    }

    /**
     * Returns the current volume index for a particular stream.
     *
     * @param streamType The stream type whose volume index is returned.