laravel composer update : the requested PHP extension dom is missing from your system

Question

I am using ubuntu 16.04, laravel 5.2 when i run update composer in my project directory its showing "the requested PHP extension dom is missing from your system" i checked installed packages of PHP, its available there

Answer 1

Installing xml-extension (php7.0-xml in my case) solved the problem

sudo apt-get install php-xml