Your friends just don't get it. While they're still bumming around in Nikes, dorms and doomed relationships, your life has recently become more serious. That's why you sometimes need to hide from their constant, mindless barrage of messages, and also why you probably won't install the newly updated Facebook Messenger app v1.7. In line with FB's "mobile first" strategy, it debuts key new functions on iOS and Android, including instant and compulsory "seen by" read receipts as well as optional "sent from" notifications. So, in addition to knowing how aloof you've become, they'll be able to track you down and slap your face.