After iPhone OS 3.1 hit, people started to notice some problems. Outside of the Exchange issues, 3.1 also lead a number of people to experience a precipitous drop in battery life. While the problems with Exchange came from Apple fixing something that was broken, the origin of these new battery issues is a mystery. According to AppleInsider, AppleCare workers are busy getting to the bottom of it right away.

They've started sending out brief, 11 question surveys to certain customers who posted in the Apple support discussion forums. Apple is also asking these users to download an attachment that allows their iPhone to log its battery life. If Apple can get some useful info on what is causing the battery drain, they should be able to fix it.

That fix could come as soon as this Friday. Sept. 25th is the day iPhone users have been waiting for since Summer; the coming of MMS functionality. If Apple can figure out a fix by then, it might end up included along with the scheduled firmware update. In all likelihood though, we've got a fair amount of waiting to do before Apple figures anything out.