Q: using iphone4s facing problem in mail version 8.1

Hi, Muthu.Nambhi.  

Thank you for visiting Apple Support Communities.  

I understand that you are experiencing an issue with mail on your iPhone 4s.  I would need more information on what exact issue you are experiencing with mail to provide a better answer.  However, here is a troubleshooting article that may help with this scenario.  

Get help with Mail on iPhone, iPad, and iPod touch

Regards