It came out November 2011. AT&T was the exclusive retailer for it, and was the first LTE phone they offered.
no.
It has Bluetooth.
Some of the notable differences are form factor sizes (Skyrocket is a touch wider, taller, thicker, and heavier), screen sizes (4.3 inches vs. 4.5 inches for the Skyrocket), HSPA+ (S2) vs. LTE (S2 Skyrocket), larger battery (Skyrocket), processor (1.2 GHz vs. 1.5GHz for the Skyrocket), internal memory (S2 comes in 16 or 32 gb versions, Skyrocket only has 16 gb...both have similar external SD capacity).
The Android OS on the Samsung Galaxy S2 Skyrocket is upgradable to Android 4.1 OS (Jelly Bean) in stock form, but could be upgraded to Android 4.4 (KitKat) if it is unlocked and rooted.
iPhone 4s
It has, and it recently upgraded again to Jelly Bean (4.1.2).
As the Samsung Galaxy S2 has reached its service life, which typically for most smartphones is 2 years, it is not expected to receive a OS update from Samsung or the carrier (AT&T in this case). However, there are a number of custom ROM's that are KitKat to choose from.
Galaxy S2 HD LTE is better
galaxy s2
galaxy s2
what is the default password for galaxy s2
Yes, when you rotate the phone horizontally, the keyboard will switch to full screen, with a small space up top to see what you're writing.