Upgrade SEP

Hi

I am going to upgrade SEP from 12.1.1 to 12.1.3 , my plan is after upgrade complete the 2 versions (12.1.1 and 12.1.3) can coxist on the same SEP console .when look into https://fileconnect.symantec.com , there are 2 files with name

Symantec_Endpoint_Protection_12.1.3_Part1_Installation_EN.exe and  Symantec_Endpoint_Protection_12.1.3_SEPM_EN.exe , what's different with 2 files and which one is suitful for my situation ?

thanks

Michael