Today is a great day for all the Samsung Galaxy S2 users that were hoping that they will get to test Marshmallow OS on their devices, as the CyanogenMod team has just rolled out the new CM 13 Nightly builds. The ROM is available for all the International Galaxy S2 I9100 model only.
The CM 13 Nightlies are some of the most popular custom Marshmallow builds currently available for tons of Android devices like the Galaxy S4, S4 Mini, S4 LTE, S5, S5 DUOS, S3 GSM and LTE models. The Galaxy S2 phone is the latest entry in the CM 13 ROM lineup and you should try it in case you want to test a Marshmallow custom ROM.
The CM 13 Nightly is based on the AOSP Android 6.0 builds, but you will get multiple other great default features designed by the CyanogenMod team, too. There were other Marshmallow ported ROMs released for the Galaxy S2, but the CM 13 builds are in a whole other league when it comes to functionality.
If you are looking to install this new CM 13 Nightly ROM on your Galaxy S2, then you will need your device to be on a rooted firmware and it should be running a custom Recovery that's based on CWM or TWRP Recoveries. Installing a custom ROM should always be applied by advanced users, as you will be forced to factory reset the device in order to make sure that it boots Android 6.0 CM 13 ROM.
Note that the CM 13 Nightlies for Galaxy S2 are still in their first development stage, which means that not everything is going to work flawlessly. You can install the first CM 13 build, but you should continue updating it using the CyanogenMod Updates menu from under Settings> About Phone section.
In case you own the Galaxy S2 device and you are looking to update it to Android 6.0 Marshmallow using CM 13 ROM, and you don't know where to start, then you can check our tutorial guide here. Tell us in comments if you've installed the new custom ROM and, make sure to list some of the best Android 6.0 features that you've spotted while testing it on your Galaxy S2 phone.