Why is the iPhone 6 Text Messages interface different from previous iPhones?

[iMore Question]

On my iPhone 4S and 5C (and presumably 5S) the Messages app shows a microphone icon to the right of the text input field that when I click and hold it allows me to create and send an audio message or voice-text.

But on my iPhone 6 there is no such icon, only "Send"

Can you tell me where that feature is on the iPhone 6?

 

[iSRS]

Is it missing all the time or just when you type? Mine is there until I start typing.

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