An iOS 7 change to Messages.app's iMessage behavior is a real problem for us. It strikes iMessage users who have intermittent iPhone network access, in our case it's the kids on the $40/year H2O wireless voice/text plan (no data). i'm not sure if it's a bug or a feature or both a bug AND a feature.
The problem is my iPhone believes #1 is an iMessage user -- perhaps because he is when he's on a WiFi network, or perhaps because he has an iCloud address. In iOS 6 I believe (can't verify) Messages.app managed the on/off network problem this way:
- if SMS received, reply with SMS
- if use iMessage and it fails, send as SMS
In iOS 7 Message.app I'm seeing
- if SMS received, but prior history of iMessage, reply with iMessage
- iMessage doesn't show a 'read' (delivered) message, but neither does it show a fail message. Message is NOT resent as SMS
The trick in today's Message.app is to watch for the 'read' indicator -- or to force an SMS resend immediately if you know the sender doesn't have a net connection. Force a SMS resend by tap and hold on the blue iMessage, then choose send as text. The message turns green (Text/SMS).
If this is a bug, I suspect the problem is with recognizing an iMessage failure.
This problem, by the way, contributed to a parent-kid fight about 'ignored' messages. It's worth knowing about.