Magento 2.0.18 is the final 2.0.x release. After March 2018, Magento 2.0.x will no longer receive security patches, quality fixes, or documentation updates.
To maintain your site's performance, security, and PCI compliance, upgrade to the latest version of Magento.

Reinstall the Magento software

A contributing developer reinstalls Magento by updating composer.json to specify the Magento product version and component versions desired and runs composer update.

To reinstall the Magento software as a contributing developer:

  1. Log in to your Magento server as a user with permissions to modify files in the Magento file system (for example, the switch to the Magento file system owner.
  2. Make a backup copy of composer.json in your Magento installation directory:

    cd <your Magento install dir>
    cp composer.json composer.json.bak
  3. Open composer.json in a text editor.
  4. Locate the following line:

     "require": {
    	"magento/product-community-edition": "<version>"
  5. Replace <version> with the version to which you want to upgrade, where <version> is the product version to use.

    (The product version is in the format 2.0.x) .

  6. Save your changes to composer.json and exit the text editor.
  7. Enter the following command:

    composer update

    Wait for dependencies to update.

  8. Install the Magento software.