iOS 5 will be presented at the WWDC on June 6, 2011, but some testers already have the future version of iOS in their terminals and are testing it with applications already available in the AppStore. The app developer company FutureTap has already received a crash report from a device that has iOS 5 installed. The crash report shows a problem related to the location APIs, so Apple probably changed some APIs related to the GPS function of iOS 5.
Just received the first iOS 5.0 crash report. MKUserLocationBreadCrumb sounds interesting.
The message above was published on Twitter by someone from FutureTap but unfortunately this was the only information. Apple has not released any beta version of iOS 5 but it seems that some people are already "playing" with the future version of iOS. It would be unusual for Apple to release a new version of iOS without developers having access to it beforehand, but anything is possible.
UPDATED: FutureTap has also published an image of the crash report received.
