Yesterday, we were concerned that AT&T might have capped iPhone 4 data upload speeds in certain areas. AT&T has responded and assures us that they have not; in fact, it's a software problem.

You may have seen some speculation that we were somehow capping data speeds. We're not. Here's the deal: It's a software issue which AT&T and Alcatel-Lucent have now jointly identified. It's only triggered under certain conditions and has only impacted uplink performance for less than 2% of our customer base — those using Laptop Connect and smartphone customers using 3G HSUPA-capable wireless devices in markets with Alcatel-Lucent equipment. Alcatel-Lucent is developing a longer-term software fix in the coming weeks, but in the meantime we have implemented an alternative that provides normal 3G uplink speeds and consistent performance for affected customers using HSUPA-capable devices.

So the problem has been identified and a fix is in the works. Just to be clear, this is not an issue with iOS 4, but with Alcatel-Lucent's software. More details about the alternative quick fix would have been nice, but if speeds are improving, that's ultimately what matters.

Were you one of the ones affected by slow upload speeds? If so, have you noticed an improvement?

[AT&T - Thanks Gregg for the tip!]