Try removing the plastic cover provided with the set, and try system will not heat up as it worked with me.
Too many apps drain battery even though they are not used, but run in background, curtail unwanted apps or install system app to handle your battery draining apps such as AVG
Don't go by what you hear few might be having problems but what you need is more important than what others have been asking for. I did buy as Samsung hangs what ever RAM. VIVO Y55S is indeed a good product as your backup gets stored in cloud storage due which phone hang is less, light, sleek etc. Rest is yours
In my opinion, do not buy a vivo smartphone. They do not provide OS upgrade and their customer support representatives are naive. I advise you to buy other brands such as huawei.
