s8+ showing errors

[nisarg3010]

I have been using this phone from past three years and now it is showing me this kind of errors, and how can i check my battery health 

[Ashwin98]

Bro what's the software version you are using with?!!
Battery no doubt, you have to change it since your phone is 3 years old....

[nisarg3010]

my battery health is 81% and its works fine i don't have complaints about it

[Anonymous]

CSC changes

[oyemukul]

did you root your phone or installed twrp.

[saltaf]

Bro, take backup and reset your phone to factory defaults.