Ok, before I ask this remember I am but a rookie! LOL! What is an OS? (insert hysterical laughter here) I am assuming "operating system" and where on my phone would i find that information?
No laughing form me
Go to options>about and you will see it there. I would assume since you didn't know that and if you bought your phone brand new, and not form a 3rd party you probably have .75 on there. Which is the last official OS released by Verizon.