SYSTEM_SETTINGS_KEY_FONT_SIZE, /**< The current system font size */
SYSTEM_SETTINGS_KEY_FONT_TYPE, /**< The current system font type */
SYSTEM_SETTINGS_KEY_MOTION_ACTIVATION, /**< Indicates whether the motion service is activated */
+ SYSTEM_SETTINGS_KEY_EMAIL_ALERT_RINGTONE, /**< The file path of the current email alert ringtone */
} system_settings_key_e;