How can i update officially to latest version.My note 8 stuck on One UI 1.0 & ANDROID 9PLEASE ASSIST

I am using SM-960F Still won't get the March security update.Please help.I was buying this phone from India.

Mine model is SM -950F, i bought this phone from uae and using it in bangladesh.Already installed samsung members apps but wont gind the One Ui Beta program notice on notice tab. How can i registered for that anf get one ui beta ..Plz share the way..