For those of you wondering where is Android 5.0 Lollipop for Galaxy S2 smartphones, I have some good and bad news.
The good news is that there are working versions of CM12 ROM alpha, which will give you the latest Android 5.0 Lollipop.
The bad news is that these ROMs are still in “alpha” stages, meaning there are many bugs. However, if you do want to try out the Android 5.0 Lollipop today, you can make a backup ROM, try Lollipop, then restore your previous ROM.
For GT-i9100 version, everything seems to work except for camera and Play Store. This is a deal breaker for most of you since without Play Store you cannot install any apps. But, you can surely try out the new Lollipop UI and mess around settings.
For SGH-i777 version, you will also have some problems with Play Store, similar to the GT-i9100 version. Oh yeah, this one is very unstable and will reboot on you easily so be careful but the camera does work.