posted this on July 26, 2011 12:20 PM
Direct Messages are currently supported on all platforms with app version 4.0 and greater, over a data connection.
If you receive a message and are on an incompatible version, you'll be prompted to update your app to receive the message.
If you send a message to a user without the app installed, they'll be sent an SMS notifying them that they've received a DM and they'll be provided a link to update their app. They won't be able to see or respond to your message without GroupMe 4.0 or without logging into the app.