So now Galaxy S II I9100 is now going to get Marshmallow 6.0 Rom in a form of CM13.We suggest you make a backup of your previous rom before flashing this.Let’s start the step by step guide on How to Flash Cyanogenmod 13 rom in Samsung Galaxy S2
You can track the development thread of Cyanogenmod 13 for Galaxy S2 from here for latest bugs and stability report.
#How to install Cyanogenmod 13 Rom in Galaxy S2
1.Download official CM13 Rom for Galaxy S2 and the appropriate Gapps 6.0 package from link given below Copy it in your in your device.
2.Now place the Cyanogenmod 13 rom and gapps 6.0 zip file in sd card.
3.Now reboot to Recovery mode (TWRP recovery recommended)
4.Then flash CM13 android marshmallow rom and gapps from the recovery in it.
5.Now Clear cache and Clear Data.
6.Reboot your device.Done! you just flash cyanogenmod 13 rom in your Samsung Galaxy S2.Enjoy Android Marshmallow 6.0.