I wouldn't be discounting the software just yet - some problems do not affect all users and depend what country you are in. The software for instance may be conflicting with Australian phone carrier settings, so it really depends where you are.
There are enough people having this issue to note as a problem. It is apparent that there is a problem as when on wifi there is no problem. Users are experiencing problems across all Australian networks sporadically, so obviously the new update doesn't agree with something there.
When people are not recieveing messages, it becomes an urgent issue to address.