According to SprintFeed, Sprint will begin locking SIM slots on the iPhone 4S beginning November 11. Contradicting claims about the locked or unlocked status of Sprint's iPhone 4S are now effectively moot, at least according to an internal Sprint memo that SprintFeed obtained. According to the memo, "all iPhone 4S devices will have the SIM locked. The locking occurs during the activation process and is invisible to the customer."
The memo notes that customers who bought and activated their iPhones before November 11 will not have their phones locked afterward, so early adopters are in the clear. This suggests that the Sprint iPhone did indeed have the ability to accept any SIM, but future iPhone 4S units activated on Sprint's network will not.
Leaving the SIM unlocked would have allowed Sprint customers to insert any SIM from the carrier of their choice while travelling internationally. Instead, future Sprint customers will be locked into Sprint's international roaming plans, just as AT&T customers have been all along. This is just the latest in a series of quite customer-hostile moves on Sprint's part, and it means any US-based customers hoping for a truly unlocked iPhone 4S handset will have to wait until Apple releases them to the market.
[via Mac Rumors]