Samsung starts rolling out Ice Cream Sandwich version of Android OS in Galaxy S2 devices in India. Worldwide, it was started rolling out in the month of March this year. Users can use Kies software to update the firmware on their mobile. Also you can update firmware directly from your mobile.
Here is a video tutorial for direct update: Thanks TheBillyAnalog.
The main reason behind delay in firmware update is the two variants of Galaxy S2 in India. These variants are I9100 and I9100G variant. Samsung wanted to release the firmware for both type of devices at the same time and ICS for I9100G wasn’t ready. Meanwhile, start upgrading your ICS and start enjoying using amazing new ICS on your mobile.