You can see this warning if you are using an older PHP application with a new version of PHP.
In order to fix warning below
Warning: strftime() [function.strftime]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'UTC' for 'UTC/0.0/no DST' instead in *path to php script* on line 34.
add the following line at the start of your PHP script:
or this line to your main .htaccess file (httpdocs/.htaccess):
php_value date.timezone America/Los_Angeles
(Change 'America/Los_Angeles' to wherever you are)
or simply contact support at https://www.mystorehelp.com and we'll do the changes for you.