Is it possible to detect (programmatically), from an iMessage app extension: from the sender side: Whether the person you are talking to is using iMessage on their end, or they are an SMS/MMS user (Such as Android or Windows phone)
Basically I need to tailor my delivery experience based on whether they can render the fully rich experience, or a minimized subset of it.
For example, for iMessages, I actually want to deliver in-line video. For MMS/SMS, i maybe only want to show an Image only, or maybe even a Link only, to avoid the recipient's SMS/MMS charges.
No API is available for this. It's a really good idea though. I suggest you file an enhancement request with Apple. [Update: if anyone from Apple happens to see this, I've filed rdar://32773566 to request this.]
One possible workaround-- depending on how your app works with these videos-- is to upload the video somewhere and then send the URL as the message. On iOS, Messages.app will render a nice preview of most videos, if the sender is in the recipient's address book or the recipient has sent messages to the sender in the past.