composer

When working with composer you will have multiple lock files. The composer.lock in your application root directory and a installed.json file inside the vendor/composer directory.

(Internal: might be obsolete)

Installation with composer:

composer require 'drupal/comment_notify'

Enable with drush:

drush pm:install comment_notify

Configure it under ../admin/config/people/comment_notify.
Select the Bundle on that you want to enable it. Chose "All Comments" under availible subscription modes and set it as default state. 
 

Nice and important feature, so that composer fails when a patch does not apply anymore.

  "extra": {
    "composer-exit-on-patch-failure": true,