I have the Black Shark 4 and found that it gives up a built in Android function. I use a VPN into a VIOP phone system. Normally you create the connection as a persistent VPN. This feature is already baked into Android but these developers actually removed the feature. When I contacted them they gave me a generic excuse and brushed me off. I just don't know why that was necessary to remove. It's better for business to add features on top of the general features you come to expect. Removing them just makes it possible to become excluded from certain established markets. Possible sign of poor management and certainly won't have any investments in this company.