My text messages don't go out since I upgraded to iOS 5

We did extensive testing of Groups during the iOS 5 beta period (several months) and had absolutely no problems with it at all, on our devices in the UK and also on a device in Canada; and that continues to be the case -- which means that overall, Groups is already compatible with iOS 5.
 
That said: we are aware of certain iOS 5 limitations on some carriers which cause issues when trying to send out a group text message. Here are some of our findings:

 

AT&T users in the US / iOS 5 users in general:

Please turn iMessage, MMS, and Group Messaging to the off position in your device settings

Tele2 users in Sweden:

Please turn MMS to the off position in your device settings (thanks very much to a user who supplied this information).

Orange users in the UK: 

MMS needs to be switched off or messages try to be sent through     iMessage and simply don\'t work. If MMS is turned off, they are sent through     normal SMS. If iMessage is turned off, they don\'t even get into the Message      application (unless MMS is also off). So, it looks like group messages default     to going through MMS, and MMS tries to send through iMessage. ( thanks very much to a user who supplied this information)

Other users:

Please try the workaround for AT&T customers.   If it doesn’t help, then please try a variety of combinations of On and Off for iMessage, MMS, SMS, and Group Messaging. Once you find a combination that allows you to send messages from Groups, please kindly let us know by writing to us at this page:

 

http://www.guidedways.com/kb/contact-us.php

 

As we get information from users with carriers, we will post updated instructions here.