iOS 7 Messages app reverts from iMessage to SMS at random I am having an issue with the Messages app on iOS 7.0.4 (11B554a) whereby on conversations that were previously all SMS and the other person purchases an iPhone, Messages reverts from sending iMessages to SMS seemingly at random. 

I have tried:


Disabling/re-enabling iMessages in the Settings app (temporary fix)
Killing Messages from the multitasking view (temporary fix)
Disabling the "Send as SMS" option in Messages settings (does not work)


Has anyone else experienced this or know of a possible solution? I am considering using a third party tool like iExplorer to export all of my conversations and starting fresh, but I really view it as a last resort since some of these conversations have been with me since the launch of the original iPhone in 2007.

Edit 1: I should point out that these are not failures to send an iMessage that results in a fallback to SMS, rather I notice as I'm composing the message that the text entry box has the subtle "Text Message" on it and the Send button is green. I perform steps #1 or #2 (typically #2) and the iMessage is sent and received just fine.

Edit 2: Further investigation has shown that when the Messages app isn't used for a long period or is suspended due to a using resource intensive app (like a 3D game), this behavior will occur -- the Messages app will show messages to the one person who I used to contact with SMS has reverted to SMS again while everyone else still shows as being iMessage capable so I don't believe my connection Apple's servers is the issue. Again, simply killing the Messages app from the multitasking view shows everyone is capable of iMessage again and iMessages are sent and received properly.
iMessage is essentially an Apple operated Instant Messenger service deployed to compete with, or augment, SMS and MMS.

iOS will use iMessage to deliver a message if there is a data connection available to Apple's servers and both the sender and recipient are known by Apple to have iMessage configured for their respective addresses.

Most likely if a person you regularly iMessage with is now sometimes receiving as SMS it is due to intermittent data connection (ie you are mobile and data service is failing). Otherwise it could be an Apple iMessage server issue - seems to crop up regularly.

Furthermore in the last three weeks several of my friends and family have reported issues with iMessage so possibly there is something deeper and worse going on with iMessage servers.

cheers