Router AMG1302 T11C update firmware

CAL18

I have the router 

Router AMG1302 T11C

Got it from my ISP post office broadband 
Can I update firmware to. .13 I'm on  12 with losing any settings

I am having WiFi connection issues currently and pobroadband say they can help me as they run out of ideas. 
#CPE_Aug

AAAAL

Hi CAL18,

You can upgrade AMG1302-T11C firmware via GUI : Maintenance -> Firmware Upgrade

May I know which WiFi connection issue you met currently?