Messages in secret chats are stored on server until downloaded by recipient. So there is no such problem like in Skype.
Push notifications also work fine there, except on iOS they don't contain any message data, just "You have a new message", probably because server doesn't know what's inside encrypted message. Although havent tried their android client.
Push notifications also work fine there, except on iOS they don't contain any message data, just "You have a new message", probably because server doesn't know what's inside encrypted message. Although havent tried their android client.