Samsung Galaxy S2 owners in the UK are getting impatient for the Ice Cream Sandwich update, which Samsung said would start rolling out on March 19.  

So far, only people on the O2 network have been issued the update. Vodafone, T-Mobile and Orange, will have to wait for the operators to finish testing the update on their devices, according to Tech Radar and SIM-free owners will get the upgrade last, a VP of Samsung told CNET exclusively.

Samsung is waiting to test the networks to ensure that the software is compatible with any network on the SIM-free device.

There is no official word on when the upgrade will reach the U.S, but Android enthusiasts could have to wait a little longer after Samsung revealed that the updates would have staggered release dates across the world. In a recent announcement, the U.S. carrier Verizon said the upgrade would be coming to Samsung devices in the near future, but no date was specified.

Meanwhile, AT&T became the first U.S carrier to bring the Android 4.0 updates to one of its devices on Friday. The operator has started rolling out the update on the HTC Vivid. 

AT&T also revealed other devices that would be getting the update in the future. These included:

LG Nitro, Motorola ATRIX 2, Motorola ATRIX 4G, Pantech Burst, Pantech Element, Samsung Captivate Glide, Samsung Galaxy Note, Samsung Galaxy S2, Samsung Galaxy S2 Skyrocket and Samsung Galaxy Tab 8.9.

Meanwhile, Samsung has started rolling out the Android 4.0.4. ICS update for the Galaxy Nexus GSM phone, according to Mobile Bloom.

Android's Ice Cream Sandwich software made Galaxy Nexus one of the most sought after phones in 2011. The latest update is expected to bring enhanced phone number recognition, smoother screen rotation and improved camera performance.

The Galaxy S2 and Galaxy Nexus were heralded as two of the most popular smartphones of 2011, with several features packed into a slim, sleek case. The Ice Cream Sandwich upgrade will bring refinements and a touchscreen that allows users to unlock the phone with their face, according to the BBC.