According to Cnet.com Amazon has given Alexa the most useful, and the most sensible update. You no longer need to say “Hey, Alexa” every time you send out a command.
This new feature is known as the Follow-Up Mode, which simply allows Alexa to listen to another command for around five seconds after sending out the last request. This would make it easier to ask Alexa to perform several actions a lot less repetitive, even though you are yet unable to use multiple commands in just one sentence. If you don’t give out the next command within five seconds, then Alexa will simply go back to sleep, and you will need to say ‘Hey, Alexa’ to wake her up. When you are done sending out commands, you can end the conversation with a simple ‘thank you’ or you can simply say ‘stop.’
This is a new feature, and hence you will need to go to the Echo app settings and turn it on. It is quite a welcome addition, and it seems as if Amazon will very soon make this as their default setting, which makes complete sense. We hope Google follows it too.