If you have upgraded maybe you have back to the default state for screensaver.
To turn off the screensaver:
edit /etc/kbd/config:
BLANK_TIME=0
POWERDOWN_TIME=0
add to /home/pi/.config/lxsession/LXDE-pi/autostart:
@xset s noblank
@xset s off
@xset -dpms
To turn off the screensaver:
edit /etc/kbd/config:
BLANK_TIME=0
POWERDOWN_TIME=0
add to /home/pi/.config/lxsession/LXDE-pi/autostart:
@xset s noblank
@xset s off
@xset -dpms