iOS7 and SMS Apps fail
if you use apps that help manage group SMS'ing iOS7 currently breaks them in varying degrees of badness.
i can no longer group message, I send to a group of 50 people daily. Now, even through the built in messaging that has all broken.
Reached out to the developer who have said Apple is aware and hopefully this will be fixed in a point update. So if you depend on such tools maybe don't update or check with the Dev of your preferred app first to see how badly your configuration will be effected.