iPhone sends iMessage, but doesn't show that it was "delivered", even though it is So after switching to my new iPhone 6s, I have been sending messages through iMessage. I haven't had any major issues. What has occurred though is that the messages send with the blue bubble (informing me that they are sending as iMessages) and the recipient receives the message and is able to respond without any issue. But the actual messages never displays the words "delivered" under them. While this isn't a major issue as they are sending without any problem, I am wondering why the words "delivered" do not show up.

P.S. the words "delivered" appear for the recipient when they respond to me.
iMessage lets you send free text, photo, and video messages to other
  iOS and OS X users anywhere in the world . Read receipts allow your
  contacts to see whether or not you've viewed a message. While some
  people may consider read receipts to be a bit stalker-ish, others may
  find them useful for work and business situations. Regardless of why
  you need them, we can help you turn them on or off no matter what iOS
  device or Mac you're using.


http://www.imore.com/how-turn-and-read-receipts-imessage

Just ask to your friends if they have disabled this feature ;)