LG G Flex 2 User Manual page 96

NOTE: Your personal data saved to the internal phone memory—including
information about your Google account and any other accounts, your system/
application data and settings, any downloaded applications and your DRM
licence—may be lost in the process of updating your phone's software.
Therefore, LG recommends that you backup your personal data before
updating your phone's software. LG does not take responsibility for any loss of
personal data.
NOTE: This feature depends on your network service provider, region and
country.
Phone software update