perl error messages and the resolutions

Issue

• The following messages are observed after upgrading from perl-5.8.8-27.el5 to perl-5.16.3-286.el7.

• Message 1:

 AH01215: Use of "do" to call subroutines is deprecated at ./jcode.pl line 291., referer: https://www.example.com/toyota/cgi-bin/ts_inq_check.cgi

• Message 2:

 AH01215: defined(%hash) is deprecated at jcode.pl line 693., referer: https://www.example.com/example/cgi-bin/contact_form/contact.cgi

• Message 3:

 AH01215: \t(Maybe you should just omit the defined()?), referer: https://www.example.com/example/cgi-bin/contact_form/contact.cgi

• Questions:

- Reason why above-mentioned messages are observed after migrating from perl-5.8.8-27.el5 to perl-5.16.3-286.el7.
- Workarond or resolution in order for the above-mentioned messages to dissapear.