This may be a little premature since I just loaded the 3.1 build last night, but so far my batter life is showing a lot of improvement.

I usually take my iPhone off the charger at 6am ever morning. It's 10:20am now my time and the battery JUST clicked down to 99%. Usually, by this time I would be around 93% to 95% or even less.

I also have received a lot of email this morning, pushing two accounts. This seems to be a very good improvement. So far, the build has been extremely stable with degradation speed, signal strength or voice quality. I can't say signal or voice quality has improved or not since mine was alway very good to start with.

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