Before revision: Smart Feature OS Smart Feature OS is a custom version of KaiOS that was developed and solely used by HMD Global for their KaiOS line of Nokia feature phone, the main differences between stock KaiOS and Smart Feature OS is mainly on the atheistic such as the icon and some UI element, including custom Nokia ringtone and notification tone.
After revision: Smart Feature OS Smart Feature OS is a custom version of KaiOS that was developed and solely used by HMD Global for their KaiOS line of Nokia feature phone, the main differences between stock KaiOS and Smart Feature OS is mainly on the aesthetics such as the icon and some UI element, including custom Nokia ringtone and notification tone.