Magento 2 How to Upgrade Magento 2.1.2 to 2.1.8 Using Composer

Upgrade/Updating Procedure of Magento 2 by following these simple steps:

Step 1: First of all, connect to your web server via SSH. Using putty or any SSH client.

Step 2: Once your SSH connection is established, you will need to navigate to your Magento 2 ROOT directory.

Step 3: Now follow the order and use the following commands:

   composer require magento/product-community-edition 2.1.8 --no-update 
   composer update 

 rm -rf pub/static/frontend/* pub/static/adminhtml/* var/cache var/composer_home var/generation var/page_cache var/view_preprocessed var/di  
 php bin/magento setup:static-content:deploy  
 php bin/magento cache:clean && php bin/magento cache:flush  

After upgrade, check your Magento version with the following command:

 php bin/magento --version  

Complete Working.