Php is very common language in today But there is strange thing on it that php supports every version for two years only and it give a complimentary support for security issues  1 year.

It means php has already revoked active support for php 5.6. this means now older version of popular framework such as wordpress and codeigniter will get outdated.

php 7.1 is  outdated now but support till next Dec 2019. So we have to move on php 7.2 very soon Although it also get end active support on Dec 2019.