Gevey Ultra S
While iOS 5.1.1 may have thrown jailbreakers a curveball, unlockers using the GEVEY Ultra S GSM with their GSM iPhone 4S will be happy to know it's safe to upgrade. According to online retailer ApplenBerry's Twitter feed, the GEVEY Ultra S GSM is compatible with iOS 5.1.1.
CDMA iPhone 4S or 4 models need to be jailbroken to use the Ultra 5.1 SIM interposer. There is no jailbreak for iOS 5.1.1 currently, but the GEVEY Ultra S does support iOS 4.1 and later (through 5.1). iPhone owners should not update to iOS 5.1.1 if they would like to keep their devices jailbroken.
There's another unlocking option for GSM iPhone 4 owners looking to use their device on multiple carriers. The latest GEVEY Ultra 5.1 SIM interposer makes this possible without jailbreaking or violating your Apple warranty. Compatible with iOS 4.1 and later (through 5.1), the product supports modem firmware versions 1.59, 2.10, 3.10.1, 4.10.1, 4.11.08, and 4.12.01.
Of course, those with a jailbroken iPhone 4 can also use the GEVEY Ultra 5.1 to unlock their devices. More options are becoming available for unlocking including the SAM package method and even official unlocking of out-of-contract iPhones on the AT&T network.
A few hardware unlock solutions for the iPhone 4S have appeared this month, but Gevey has released a Verizon and Sprint unlocking solution. The Gevey Ultra S claims to unlock both GSM and CDMA, unlike the R-SIM and TP-SIM which do not work with Sprint models.
The new SIM interposer requires that your iPhone be jailbroken, not be running iOS 5.1 or higher and is on one of the following basebands: 1.0.11, 1.0.13, 1.0.14. This is also the only known solution for Sprint handsets. The Gevey Ultra S is $60 and will be available at the end of this month.