Signal, the app that promises encrypted messaging between users, has stopped working in China. Users have found that the only way to get it up and working is to run it while connected to a virtual private network (VPN). China, over the last few years, has restricted encrypted communication apps and it looks like Signal might be the latest app to fall. The app still appears in the Apple app store in China and is working in Hong Kong. We will update this post if it begins working once again.