Since late yesterday, MacRumors has received a few reports of users who have seen their devices running various beta versions of iOS 5 shutting down and returning to activation mode. The reports have been sporadic, with some users suggesting that earlier beta versions may simply have been expiring and been disabled by Apple.

But according to a report from Karthik.K (via AppleInsider), the deactivations appear to be a concerted effort by Apple to crack down on registered developers who have been selling off extra beta slots to offer non-developers access to iOS 5 beta versions. Developers who have sold off their slots are apparently reporting that Apple has shut down their accounts over the violation of the company's developer terms, which limit beta iOS installations to the developer's own devices for testing purposes.

Many of my developer friends have reported that Apple has sent an email warning which said that they have identified the developer to be selling his slots for some users to get early preview of iOS. And Apple has started closing the developer accounts for selling the slots and also, have flagged the UDIDs associated with that dev account, thus making the iOS 5 device unusable. Many developers have received this letter and immediately banned their account from the developer’s program. Once Apple locks your iOS device, the phone will enter the initial setup mode asking you to connect to a WiFi network. And nothing happens more than that.

Apple allows developers to register up to 100 devices to a single developer account, which costs $99 per year. Each developer can submit a list of Unique Device Identifiers (UDIDs) to be registered under their account, and some users have taken to selling off those device slots to non-developers for $5-10 apiece in order to pay for their own developer access and make a small profit. Going even further, entire websites have even sprung up to facilitate the direct sale of such slots.

As a result of those beta slot sales, access to the iOS 5 has been relatively wide open, facilitating significant disclosures about the next-generation mobile operating system despite many of the details technically being covered by non-disclosure agreements between Apple and its developers.

It is unclear why it has taken Apple so long to crack down on the behavior, as the selling of beta slots has been an open secret for quite some time. iOS 5 is set for a public release sometime this "fall", with the general consensus being that it should appear alongside the iPhone 5 in September or October.

Update: Most of those reporting that they were affected by the issue note that they were running either Beta 1 or Beta 2 of iOS 5, both of which have expired. We have received scattered reports of users on Beta 3 and Beta 4 being affected, but those may be erroneous. Consequently, the issue may simply be expiring early beta versions as we initially supposed.

We are still looking for more reports of users on iOS Beta 3 or the current Beta 4 who can confirm being affected.