I'm using the Nokia 6 in Chinese mainland. For some reasons I have to access Google services through VPN by using a Shadowsocks client. However the SS client got kill every time when screen went off for a little while. And I have to re-launch the app and re-connect to keep the VPN tunnel alive. It was very annoying by doing this. I know it makes sense killing background apps to keep system performance. But an entrance should be left to let us choose which apps can be keep in white list.