After bringing the update to its UK subscribers, T-Mobile will be among the last in the Galaxy S II family to enable Android version 4.0, also known as Ice Cream Sandwich.
Users should be receiving automatic notifications of the upgrade, but there is the option to manually check for updates through the phone's Settings menu.
Last time Google posted numbers, last month, around 2% of all active Android devices are running version 4.0 or later, while manufacturers have been forced to be conservative about when they expect to get their devices updated.
Ice Cream Sandwich is one of the biggest updates to Android yet, and includes such features as scanning your face to unlock the phone, a much more robust speech-to-text software program, and an entire platform of data sharing that focuses on Near Field Communication (NFC) for phones that have supported hardware.
NFC so far has been mostly focused on using your phone as a payment device in retail stores, but with Ice Cream Sandwich's Android Beam, it can also allow users to easily share contact information, Youtube videos, or website addresses simply by waving two phones next to each other.
The rollout of ICS to the Galaxy S II line across multiple carriers has single-handedly helped boost the amount of devices running on the new platform. There had been many problems in the beginning of the ICS rollout phase, but it seems Google has gotten those issues under control.
Several other manufacturers have pledged support for the new update, and a bunch of phones currently running an older version of Android will be eligible to upgrade to Ice Cream Sandwich beginning in the coming months.