error message "Use of undefined constant" and " Function session_is_registered() is deprecated "

if you got error message when run PHP applications below
"Use of undefined constant " .....

please set as below at php.ini

error_reporting = E_ALL & ~E_NOTICE

then if you got error as below

"Deprecated: Function session_is_registered() is deprecated "

the issue due to you use different version of PHP
please set as below at php.ini

error_reporting = E_ALL & ~E_NOTICE & ~E_DEPRECATED

don't forget to restart Apache after changes php.ini !