I don't have software update on my phone

[redongashi16]

Hello guys,i recently bought my Galaxy S6 SM-G920F which has Android 5.1.1 and i wanted to update it to Marshmallow.First thing that came to my mind was the OTA update but when i opened settings and went to About Phone i don't see software update option on it.In Smart Switch it says: Your device software is up to date: Ol1(XXX)
In about phone it says my software is Official.

 

[lucianus_luciferus]

probably because the phone is rooted.
in the second screenshot
Root access Yes

 

[redongashi16]

yes but in phone settings it says Official doesnt that change to Modified when rooted?

 

[Rukbat]

Not always. (Rooting at its base is just the addition of one file to the phone, and that normally doesn't trigger the "Custom" notice if it's done correctly - which it seldom is.)

 

[redongashi16]

alright i downloaded the root checker and it says im root so i guess it definitely is,thank you very much